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1.
Chinese Journal of Biotechnology ; (12): 418-428, 2021.
Article in Chinese | WPRIM | ID: wpr-878572

ABSTRACT

As an extremely important organelle in eukaryotic cells, endoplasmic reticulum (ER) plays a key role in the synthesis and processing of biomacromolecules, material transport, ion homeostasis maintenance, signal transduction, exchange of materials and signals between organelles. Many important human diseases, such as cancers, autoimmune diseases, pathogenic infections, neurodegenerative diseases and diabetes, are closely related to ER dysfunction. With the development of nanotechnology, the exploration and application of ER-targeted nanodrugs gradually become a research hotspot in the field of nanomedicine, bioengineering, material chemistry and other fields. In this paper, the relationship between ER dysfunction and disease occurrence, the principle of designing ER-targeted nanodrugs and their biomedical application are reviewed. ER-targeted nanodrugs are designed based on nanodrug carriers or self-assembly of bioactive molecules. These nanodrugs could target the ER in an active or passive manner and function by disrupting or maintaining the ER functions. The ER-targeting nanodrugs have a wide application prospect in cancer therapy, immune regulation, nervous system repairment, and so on.


Subject(s)
Endoplasmic Reticulum , Endoplasmic Reticulum Stress , Homeostasis , Humans , Neoplasms/drug therapy , Signal Transduction
2.
Article in Chinese | WPRIM | ID: wpr-878543

ABSTRACT

Endoplasmic reticulum (ER) is an important organelle where folding and post-translational modification of secretory and transmembrane proteins take place. During virus infection, cellular or viral unfolded and misfolded proteins accumulate in the ER in an event called ER stress. To maintain the equilibrium homeostasis of the ER, signal-transduction pathways, known as unfolded protein response (UPR), are activated. The viruses in turn manipulate UPR to maintain an environment favorable for virus survival and replication. Herpesviruses are enveloped DNA viruses that produce over 70 viral proteins. Modification and maturation of large quantities of viral glycosylated envelope proteins during virus replication may induce ER stress, while ER stress play both positive and negative roles in virus infection. Here we summarize the research progress of crosstalk between herpesvirus infection and the virus-induced ER stress.


Subject(s)
Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Stress , Herpesviridae , Signal Transduction , Unfolded Protein Response
3.
Mem. Inst. Oswaldo Cruz ; 116: e200443, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154874

ABSTRACT

BACKGROUND The coronaviruses (CoVs) called the attention of the world for causing outbreaks of severe acute respiratory syndrome (SARS-CoV), in Asia in 2002-03, and respiratory disease in the Middle East (MERS-CoV), in 2012. In December 2019, yet again a new coronavirus (SARS-CoV-2) first identified in Wuhan, China, was associated with a severe respiratory infection, known today as COVID-19. This new virus quickly spread throughout China and 30 additional countries. As result, the World Health Organization (WHO) elevated the status of the COVID-19 outbreak from emergency of international concern to pandemic on March 11, 2020. The impact of COVID-19 on public health and economy fueled a worldwide race to approve therapeutic and prophylactic agents, but so far, there are no specific antiviral drugs or vaccines available. In current scenario, the development of in vitro systems for viral mass production and for testing antiviral and vaccine candidates proves to be an urgent matter. OBJECTIVE The objective of this paper is study the biology of SARS-CoV-2 in Vero-E6 cells at the ultrastructural level. METHODS In this study, we documented, by transmission electron microscopy and real-time reverse transcription polymerase chain reaction (RT-PCR), the infection of Vero-E6 cells with SARS-CoV-2 samples isolated from Brazilian patients. FINDINGS The infected cells presented cytopathic effects and SARS-CoV-2 particles were observed attached to the cell surface and inside cytoplasmic vesicles. The entry of the virus into cells occurred through the endocytic pathway or by fusion of the viral envelope with the cell membrane. Assembled nucleocapsids were verified inside rough endoplasmic reticulum cisterns (RER). Viral maturation seemed to occur by budding of viral particles from the RER into smooth membrane vesicles. MAIN CONCLUSIONS Therefore, the susceptibility of Vero-E6 cells to SARS-CoV-2 infection and the viral pathway inside the cells were demonstrated by ultrastructural analysis.


Subject(s)
Humans , Animals , Vero Cells/virology , Cytoplasmic Vesicles/virology , Cytopathogenic Effect, Viral , SARS-CoV-2/physiology , Chlorocebus aethiops , Nucleocapsid , Reverse Transcriptase Polymerase Chain Reaction , Microscopy, Electron, Transmission , Endocytosis , Endoplasmic Reticulum/virology , Virus Internalization , Real-Time Polymerase Chain Reaction
4.
Rev. méd. Chile ; 148(2): 216-223, feb. 2020. graf
Article in Spanish | LILACS | ID: biblio-1115779

ABSTRACT

The clinical features of Alzheimer's disease (AD), for example the progressive memory loss, are produced by neuronal loss and synaptic dysfunction. These events have been associated with histopathological alterations in AD brain, including the presence of amyloid plaques and neurofibrillary tangles. Recent studies suggest that cellular stress produced by the aggregation of misfolded proteins leads to alterations in protein homeostasis, that is regulated for the most part by endoplasmic reticulum (ER). The ER is the main compartment involved in the folding and secretion of proteins and is drastically affected in AD neurons. Recent evidence implicates the participation of adaptive responses to stress within the ER in the disease process through a signaling pathway known as the Unfolded Protein Response (UPR) which alleviates the protein aggregation and ER stress. Based on the involvement of ER stress in several diseases, efforts are being done to identify small molecules that can inhibit or activate selective UPR components. Here, we review the findings suggesting a functional role of ER stress in the etiology of AD. Possible therapeutic strategies to mitigate ER stress in the context of AD are discussed.


Subject(s)
Humans , Alzheimer Disease , Signal Transduction , Endoplasmic Reticulum , Unfolded Protein Response , Endoplasmic Reticulum Stress
5.
Chinese Medical Journal ; (24): 2599-2609, 2020.
Article in English | WPRIM | ID: wpr-877854

ABSTRACT

Mitochondrial injury and endoplasmic reticulum (ER) stress are considered to be the key mechanisms of renal ischemia-reperfusion (I/R) injury. Mitochondria are membrane-bound organelles that form close physical contact with a specific domain of the ER, known as mitochondrial-associated membranes. The close physical contact between them is mainly restrained by ER-mitochondria tethering complexes, which can play an important role in mitochondrial damage, ER stress, lipid homeostasis, and cell death. Several ER-mitochondria tethering complex components are involved in the process of renal I/R injury. A better understanding of the physical and functional interaction between ER and mitochondria is helpful to further clarify the mechanism of renal I/R injury and provide potential therapeutic targets. In this review, we aim to describe the structure of the tethering complex and elucidate its pivotal role in renal I/R injury by summarizing its role in many important mechanisms, such as mitophagy, mitochondrial fission, mitochondrial fusion, apoptosis and necrosis, ER stress, mitochondrial substance transport, and lipid metabolism.


Subject(s)
Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Stress , Humans , Mitochondria , Mitochondrial Membranes/metabolism , Mitophagy , Reperfusion Injury/metabolism
6.
Acta Physiologica Sinica ; (6): 190-204, 2020.
Article in Chinese | WPRIM | ID: wpr-827068

ABSTRACT

Endoplasmic reticulum (ER) is an important organelle for protein folding, post-transcriptional modification and transport, which plays an important role in maintaining cell homeostasis. A variety of internal and external environmental stimuli can cause the accumulation of misfolded or unfolded proteins in the endoplasmic reticulum, and then result in ER stress. ER stress activates the unfolded protein response (UPR) and initiates a cluster of downstream signals to maintain ER homeostasis. However, severe and persistent ER stress activates UPR, which eventually leads to apoptosis and diseases. In recent years, a lot of researches suggest that ER stress plays an important role in the pathogenesis of various cardiovascular diseases (CVD), including ischemic heart disease, diabetic cardiomyopathy, heart failure, atherosclerosis and vascular calcification, high blood pressure and aortic aneurysm. ER stress might be one of the important targets for treatment of multiple CVD. Herein, the regulation mechanism of ER stress by activating UPR pathways in various common CVD and the new research advances in relationship of ER stress and CVD are briefly reviewed.


Subject(s)
Apoptosis , Cardiovascular Diseases , Endoplasmic Reticulum , Endoplasmic Reticulum Stress , Humans , Unfolded Protein Response
7.
Article in English | WPRIM | ID: wpr-740562

ABSTRACT

PURPOSE: Protein overloading in the endoplasmic reticulum (ER) leads to endoplasmic reticulum stress, which exacerbates various disease conditions. Emodin, an anthraquinone compound, is known to have several health benefits. The effect of emodin against palmitic acid (PA) - induced ER stress in HepG2 cells was investigated. METHODS: HepG2 cells were treated with varying concentrations of palmitic acid to determine the working concentration that induced ER stress. ER stress associated genes such as ATF4, XBP1s, CHOP and GRP78 were checked using RT- PCR. In addition, the expression levels of unfolded protein response (UPR) associated proteins such as IRE1α, eIF2α and CHOP were checked using immunoblotting to confirm the induction of ER stress. The effect of emodin on ER stress was analyzed by treating HepG2 cells with 750 µM palmitic acid and varying concentrations of emodin, then analyzing the expression of UPR associated genes. RESULTS: It was evident from the mRNA and protein expression results that palmitic acid significantly increased the expression of UPR associated genes and thereby induced ER stress. Subsequent treatment with emodin reduced the mRNA expression of ATF4, GRP78, and XBP1s. Furthermore, the protein levels of p-IRE1α, p-elF2α and CHOP were also reduced by the treatment of emodin. Analysis of sirtuin mRNA expression showed that emodin increased the levels of SIRT4 and SIRT7, indicating a possible role in decreasing the expression of UPR-related genes. CONCLUSION: Altogether, the results suggest that emodin could exert a protective effect against fatty acid-induced ER stress and could be an agent for the management of various ER stress related diseases.


Subject(s)
Emodin , Endoplasmic Reticulum Stress , Endoplasmic Reticulum , Hep G2 Cells , Immunoblotting , Insurance Benefits , Palmitic Acid , Polymerase Chain Reaction , RNA, Messenger , Sirtuins , Unfolded Protein Response
8.
Article in English | WPRIM | ID: wpr-739802

ABSTRACT

BACKGROUND: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. CONCLUSION: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.


Subject(s)
Animals , Apoptosis , Blotting, Western , Calcium-Transporting ATPases , Cyclin-Dependent Kinase 5 , Diabetes Mellitus, Type 2 , Down-Regulation , Endoplasmic Reticulum Stress , Endoplasmic Reticulum , Gene Expression , Genes, Homeobox , Glucose , Hyperglycemia , Insulin-Secreting Cells , Membrane Potential, Mitochondrial , Polymerase Chain Reaction , Rats , Reactive Oxygen Species , Reticulum , Reverse Transcription , Up-Regulation
9.
Article in English | WPRIM | ID: wpr-763024

ABSTRACT

Trypanosoma cruzi infection results in debilitating cardiomyopathy, which is a major cause of mortality and morbidity in the endemic regions of Chagas disease (CD). The pathogenesis of Chagasic cardiomyopathy (CCM) has been intensely studied as a chronic inflammatory disease until recent observations reporting the role of cardio-metabolic dysfunctions. In particular, we demonstrated accumulation of lipid droplets and impaired cardiac lipid metabolism in the hearts of cardiomyopathic mice and patients, and their association with impaired mitochondrial functions and endoplasmic reticulum (ER) stress in CD mice. In the present study, we examined whether treating infected mice with an ER stress inhibitor can modify the pathogenesis of cardiomyopathy during chronic stages of infection. T. cruzi infected mice were treated with an ER stress inhibitor 2-Aminopurine (2AP) during the indeterminate stage and evaluated for cardiac pathophysiology during the subsequent chronic stage. Our study demonstrates that inhibition of ER stress improves cardiac pathology caused by T. cruzi infection by reducing ER stress and downstream signaling of phosphorylated eukaryotic initiation factor (P-elF2α) in the hearts of chronically infected mice. Importantly, cardiac ultrasound imaging showed amelioration of ventricular enlargement, suggesting that inhibition of ER stress may be a valuable strategy to combat the progression of cardiomyopathy in Chagas patients.


Subject(s)
2-Aminopurine , Animals , Cardiomyopathies , Chagas Disease , Endoplasmic Reticulum , Endoplasmic Reticulum Stress , Heart , Humans , Lipid Droplets , Lipid Metabolism , Mice , Mortality , Pathology , Peptide Initiation Factors , Trypanosoma cruzi , Ultrasonography
10.
Article in English | WPRIM | ID: wpr-761800

ABSTRACT

Gα(q)-coupled receptor stimulation was implied in the activation process of transient receptor potential canonical (TRPC)1/4 and TRPC1/5 heterotetrameric channels. The inactivation occurs due to phosphatidylinositol 4,5-biphosphate (PI(4,5)P₂) depletion. When PI(4,5)P₂ depletion was induced by muscarinic stimulation or inositol polyphosphate 5-phosphatase (Inp54p), however, the inactivation by muscarinic stimulation was greater compared to that by Inp54p. The aim of this study was to investigate the complete inactivation mechanism of the heteromeric channels upon Gα(q)-phospholipase C β (Gα(q)-PLCβ) activation. We evaluated the activity of heteromeric channels with electrophysiological recording in HEK293 cells expressing TRPC channels. TRPC1/4 and TRPC1/5 heteromers undergo further inhibition in PLCβ activation and calcium/protein kinase C (PKC) signaling. Nevertheless, the key factors differ. For TRPC1/4, the inactivation process was facilitated by Ca²⁺ release from the endoplasmic reticulum, and for TRPC1/5, activation of PKC was concerned mostly. We conclude that the subsequent increase in cytoplasmic Ca²⁺ due to Ca²⁺ release from the endoplasmic reticulum and activation of PKC resulted in a second phase of channel inhibition following PI(4,5)P₂ depletion.


Subject(s)
Calcium , Cytoplasm , Endoplasmic Reticulum , GTP-Binding Proteins , HEK293 Cells , Inositol , Phosphatidylinositol 4,5-Diphosphate , Phospholipases , Phosphotransferases , Protein Kinase C , Transient Receptor Potential Channels , Type C Phospholipases
11.
Article in English | WPRIM | ID: wpr-766018

ABSTRACT

BACKGROUND: Most triple-negative breast cancers (TNBCs) have a high histologic grade, are associated with high endoplasmic stress, and possess a high frequency of TP53 mutations. TP53 missense mutations lead to the production of mutant p53 protein and usually show high levels of p53 protein expression. Tumor-infiltrating lymphocytes (TILs) accumulate as part of the anti-tumor immune response and have a strong prognostic and predictive significance in TNBC. We aimed to elucidate the association between p53 expression and the amount of TILs in TNBC. METHODS: In 678 TNBC patients, we evaluated TIL levels and expression of endoplasmic stress molecules. Immunohistochemical examination of p53 protein expression was categorized into three groups: no, low, and high expression. RESULTS: No, low, and high p53 expression was identified in 44.1% (n = 299), 20.1% (n = 136), and 35.8% (n = 243) of patients, respectively. Patients with high p53 expression showed high histologic grade (p < .001), high TIL levels (p = .009), and high expression of endoplasmic reticulum stress-associated molecules (p-eIF2a, p = .013; XBP1, p = .007), compared to patients with low p53 expression. There was no significant difference in disease-free (p = .406) or overall survival rates (p = .444) among the three p53 expression groups. CONCLUSIONS: High p53 expression is associated with increased expression of endoplasmic reticulum stress molecules and TIL influx.


Subject(s)
Breast Neoplasms , Endoplasmic Reticulum , Endoplasmic Reticulum Stress , Humans , Lymphocytes, Tumor-Infiltrating , Mutation, Missense , Survival Rate , Triple Negative Breast Neoplasms
12.
Article in English | WPRIM | ID: wpr-766013

ABSTRACT

BACKGROUND: Development of chemotherapeutics for the treatment of advanced hepatocellular carcinoma (HCC) has been lagging. Screening of candidate therapeutic agents by using patient-derived preclinical models may facilitate drug discovery for HCC patients. METHODS: Four primary cultured HCC cells from surgically resected tumor tissues and six HCC cell lines were used for high-throughput screening of 252 drugs from the Prestwick Chemical Library. The efficacy and mechanisms of action of the candidate anti-cancer drug were analyzed via cell viability, cell cycle assays, and western blotting. RESULTS: Guanabenz acetate, which has been used as an antihypertensive drug, was screened as a candidate anti-cancer agent for HCC through a drug sensitivity assay by using the primary cultured HCC cells and HCC cell lines. Guanabenz acetate reduced HCC cell viability through apoptosis and autophagy. This occurred via inhibition of growth arrest and DNA damage-inducible protein 34, increased phosphorylation of eukaryotic initiation factor 2α, increased activating transcription factor 4, and cell cycle arrest. CONCLUSIONS: Guanabenz acetate induces endoplasmic reticulum stress–related cell death in HCC and may be repositioned as an anti-cancer therapeutic agent for HCC patients.


Subject(s)
Activating Transcription Factor 4 , Apoptosis , Autophagy , Blotting, Western , Carcinoma, Hepatocellular , Cell Cycle , Cell Cycle Checkpoints , Cell Death , Cell Line , Cell Survival , DNA , Drug Discovery , Drug Repositioning , Endoplasmic Reticulum , Guanabenz , Humans , Mass Screening , Peptide Initiation Factors , Phosphorylation , Primary Cell Culture
13.
Immune Network ; : e34-2019.
Article in English | WPRIM | ID: wpr-764026

ABSTRACT

Neutrophilic granule protein (NGP) was previously reported as a granular protein of neutrophils in mouse, but the function has not been known clearly. We found the presence of the possible signal peptide in NGP and validated this protein is circulating in the bloodstream. In our findings, NGP is being modified post-translationally in Golgi apparatus and endoplasmic reticulum, which is a universal character of secretory molecules with a signal peptide. The secreted NGP protein could be detected both in vitro and in vivo. NGP has sequence similarity with an antimicrobial protein cathelicidin, and we observed the aspect of inflammation of NGP. Interestingly, NGP interacts with the complex of LPS and LPS binding protein (LBP). This interaction blocks the binding of the complex of LPS and LBP to TLR4 and the downstream inflammatory signals. Furthermore, the inhibitory function of NGP against the inflammatory effect of LPS could be observed in both in vitro and in vivo. With these findings, we report NGP is a novel secretory protein to mask LPS and inhibit its function.


Subject(s)
Animals , Carrier Proteins , Cytokines , Endoplasmic Reticulum , Golgi Apparatus , In Vitro Techniques , Inflammation , Lipopolysaccharides , Masks , Mice , Neutrophils , Protein Binding , Protein Sorting Signals
14.
Article in English | WPRIM | ID: wpr-785705

ABSTRACT

BACKGROUND: Chronic exposure to elevated levels of free fatty acids contributes to pancreatic β-cell dysfunction. Although it is well known that metformin induces cellular energy depletion and a concomitant activation of AMP-activated protein kinase (AMPK) through inhibition of the respiratory chain, previous studies have shown inconsistent results with regard to the action of metformin on pancreatic β-cells. We therefore examined the effects of metformin on pancreatic β-cells under lipotoxic stress.METHODS: NIT-1 cells and mouse islets were exposed to palmitate and treated with 0.05 and 0.5 mM metformin. Cell viability, glucose-stimulated insulin secretion, cellular adenosine triphosphate, reactive oxygen species (ROS) levels and Rho kinase (ROCK) activities were measured. The phosphorylation of AMPK was evaluated by Western blot analysis and mRNA levels of endoplasmic reticulum (ER) stress markers and NADPH oxidase (NOX) were measured by real-time quantitative polymerase chain reaction analysis.RESULTS: We found that metformin has protective effects on palmitate-induced β-cell dysfunction. Metformin at a concentration of 0.05 mM inhibits NOX and suppresses the palmitate-induced elevation of ER stress markers and ROS levels in a AMPK-independent manner, whereas 0.5 mM metformin inhibits ROCK activity and activates AMPK.CONCLUSION: This study suggests that the action of metformin on β-cell lipotoxicity was implemented by different molecular pathways depending on its concentration. Metformin at a usual therapeutic dose is supposed to alleviate lipotoxic β-cell dysfunction through inhibition of oxidative stress and ER stress.


Subject(s)
Adenosine Triphosphate , AMP-Activated Protein Kinases , Animals , Blotting, Western , Cell Survival , Electron Transport , Endoplasmic Reticulum , Endoplasmic Reticulum Stress , Fatty Acids, Nonesterified , Insulin , Insulin-Secreting Cells , Metformin , Mice , NADPH Oxidases , Oxidative Stress , Phosphorylation , Polymerase Chain Reaction , Reactive Oxygen Species , rho-Associated Kinases , RNA, Messenger
15.
Article in English | WPRIM | ID: wpr-763368

ABSTRACT

PURPOSE: Canine influenza virus (CIV), H3N2, carries potentiality for zoonotic transmission and genetic assortment which raises a concern on possible epidemics, and human threats in future. To manage possible threats, the development of rapid and effective methods of CIV vaccine production is required. The plant provides economical, safe, and robust production platform. We investigated whether hemagglutinin (HA) antigen from Korea-originated CIV could be produced in Nicotiana benthamiana and lettuce, Lactuca sativa by a DNA viral vector system. MATERIALS AND METHODS: We used DNA sequences of the HA gene from Korean CIV strain influenza A/canine/Korea/S3001/2015 (H3N2) for cloning into a geminiviral expression vectors to express recombinant HA (rHA) antigen in the plant. Agrobacterium-mediated infiltration was performed to introduce HA-carrying vector into host plants cells. Laboratory-grown N. benthamiana, and grocery-purchased or hydroponically-grown lettuce plant leaves were used as host plants. RESULTS: CIV rHA antigen was successfully expressed in host plant species both N. benthamiana and L. sativa by geminiviral vector. Both complex-glycosylated and basal-glycosylated form of rHA were produced in lettuce, depending on presence of endoplasmic reticulum (ER) retention signal. In terms of rHA expression level, canine HA (H3N2) showed preference to the native signal peptide than ER retention signal peptide in the tested geminiviral vector system. CONCLUSION: Grocery-purchased lettuce leaves could serve as an instant host system for the transient expression of influenza antigen at the time of emergency. The geminiviral vector was able to induce expression of complex-glycosylated and basal-glycosylated rHA in lettuce and tobacco.


Subject(s)
Base Sequence , Clone Cells , Cloning, Organism , DNA , Emergencies , Endoplasmic Reticulum , Hemagglutinins , Humans , Influenza, Human , Lettuce , Orthomyxoviridae , Plant Leaves , Plants , Protein Sorting Signals , Tobacco
16.
Article in English | WPRIM | ID: wpr-763301

ABSTRACT

OBJECTIVES: Endoplasmic reticulum (ER) stress is known to be associated with inflammatory airway diseases, and three major transmembrane receptors: double-stranded RNA-activated protein kinase-like ER kinase, inositol requiring enzyme 1, and activating transcription factor 6 (ATF6) play important roles in ER stress-related proinflammatory signaling. However, the effects of ER stress and these three major signaling pathways on the regulation of the production of airway mucins in human nasal airway epithelial cells have not been elucidated. METHODS: In primary human nasal epithelial cells, the effect of tunicamycin (an ER stress inducer) and 4-phenylbutyric acid (4-PBA, ER stress inhibitor) on the expression of MUC5AC and MUC5B was investigated by reverse transcriptasepolymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and immunoblot analysis. Small interfering RNA (siRNA) transfection was used to identify the mechanisms involved. RESULTS: Tunicamycin increased the expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules, including spliced X-box binding protein 1 (XBP-1), transcription factor CCAAT-enhancer-binding protein homologous protein (CHOP), and ATF6. In addition, 4-PBA attenuated the tunicamycin-induced expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules. Furthermore, siRNA knockdowns of XBP-1, CHOP, and ATF6 blocked the tunicamycin-induced mRNA expressions and glycoprotein productions of MUC5AC and MUC5B. CONCLUSION.: These results demonstrate that ER stress plays an important role in the regulation of MUC5AC and MUC5B via the activations of XBP-1, CHOP, and ATF6 in human nasal airway epithelial cells.


Subject(s)
Activating Transcription Factor 6 , Carrier Proteins , CCAAT-Enhancer-Binding Proteins , Endoplasmic Reticulum Stress , Endoplasmic Reticulum , Epithelial Cells , Glycoproteins , Humans , Immunoenzyme Techniques , Inositol , Mucins , Phosphotransferases , Real-Time Polymerase Chain Reaction , RNA, Messenger , RNA, Small Interfering , Transcription Factor CHOP , Transcription Factors , Transfection , Tunicamycin
17.
Article in English | WPRIM | ID: wpr-741710

ABSTRACT

BACKGROUND/OBJECTIVES: Inflammatory Bowel Disease (IBD) has rapidly escalated in Asia (including Korea) due to increasing westernized diet patterns subsequent to industrialization. Factors associated with endoplasmic reticulum (ER) stress are demonstrated to be one of the major causes of IBD. This study was conducted to investigate the effect of Lycium barbarum (L. barbarum) on ER stress. MATERIALS/METHODS: Mouse embryonic fibroblast (MEF) cell line and polarized Caco-2 human intestinal epithelial cells were treated with crude extract of the L. chinense fruit (LF). Paracellular permeability was measured to examine the effect of tight junction (TJ) integrity. The regulatory pathways of ER stress were evaluated in MEF knockout (KO) cell lines by qPCR for interleukin (IL) 6, IL8 and XBP1 spliced form (XBP1s). Immunoglobulin binding protein (BiP), XBP1s and CCAAT/enhancer-binding homologous protein (CHOP) expressions were measured by RT-PCR. Scanning Ion Conductance Microscopy (SICM) at high resolution was applied to observe morphological changes after treatments. RESULTS: Exposure to LF extract strengthened the TJ, both in the presence and absence of inflammation. In polarized Caco-2 pretreated with LF, induction in the expression of proinflammatory marker IL8 was not significant, whereas ER stress marker XBP1s expression was significantly increased. In wild type (wt) MEF cells, IL6, CHOP and XBP1 spliced form were dose-dependently induced when exposed to 12.5–50 µg/mL extract. However, absence of XBP1 or IRE1α in MEF cells abolished this effect. CONCLUSION: Results of this study show that LF treatment enhances the barrier function and reduces inflammation and ER stress in an IRE1α-XBP1-dependent manner. These results suggest the preventive effect of LF on healthy intestine, and the possibility of reducing the degree of inflammatory symptoms in IBD patients.


Subject(s)
Animals , Asia , Carrier Proteins , Cell Line , Diet , Endoplasmic Reticulum , Epithelial Cells , Fibroblasts , Fruit , Humans , Immunoglobulins , Inflammation , Inflammatory Bowel Diseases , Interleukin-6 , Interleukin-8 , Interleukins , Intestines , Lycium , Mice , Microscopy , Permeability , Tight Junctions
18.
Article in English | WPRIM | ID: wpr-719716

ABSTRACT

PURPOSE: In the presence of interferon, proteasome subunits are replaced by their inducible counterparts to form an immunoproteasome (IP) plays a key role in generation of antigenic peptides presented by MHC class I molecules, leading to elicitation of a T cell‒mediated immune response. Although the roles of IP in other cancers, and inflammatory diseases have been extensively studied, its significance in breast cancer is unclear. MATERIALS AND METHODS: We investigated the expression of LMP7, an IP subunit, and its relationship with immune system components in two breast cancer cohorts. RESULTS: In 668 consecutive breast cancer cohort, 40% of tumors showed high level of LMP7 expression, and tumors with high expression of LMP7 had more tumor-infiltrating lymphocytes (TILs) in each subtype of breast cancer. In another cohort of 681 triple-negative breast cancer patients cohort, the expression of LMP7 in tumor cells was significantly correlated with the amount of TILs and the expression of interferon-associated molecules (MxA [p < 0.001] and PKR [p < 0.001]), endoplasmic reticulum stress-associated molecules (PERK [p=0.012], p-eIF2a [p=0.001], and XBP1 [p < 0.001]), and damage-associated molecular patterns (HMGN1 [p < 0.001] and HMGB1 [p < 0.001]). Patients with higher LMP7 expression had better disease-free survival outcomes than those with no or low expression in the positive lymph node metastasis group (p=0.041). CONCLUSION: Close association between the TIL levels and LMP7 expression in breast cancer indicates that better antigen presentation through greater LMP7 expression might be associated with more TILs.


Subject(s)
Antigen Presentation , Breast Neoplasms , Breast , Cohort Studies , Disease-Free Survival , Endoplasmic Reticulum , HLA Antigens , HMGB1 Protein , Humans , Immune System , Interferons , Lymph Nodes , Lymphocytes, Tumor-Infiltrating , Neoplasm Metastasis , Peptides , Proteasome Endopeptidase Complex , Triple Negative Breast Neoplasms
19.
Article in English | WPRIM | ID: wpr-719643

ABSTRACT

The apoptotic effects of shikonin (5,8-dihydroxy-2-[(1R)-1-hydroxy-4-methylpent-3-enyl]naphthalene-1,4-dione) on the human colon cancer cell line SNU-407 were investigated in this study. Shikonin showed dose-dependent cytotoxic activity against SNU-407 cells, with an estimated IC50 value of 3 µM after 48 h of treatment. Shikonin induced apoptosis, as evidenced by apoptotic body formation, sub-G1 phase cells, and DNA fragmentation. Shikonin induced apoptotic cell death by activating mitogen-activated protein kinase family members, and the apoptotic process was mediated by the activation of endoplasmic reticulum (ER) stress, leading to activation of the PERK/elF2α/CHOP apoptotic pathway, and mitochondrial Ca2+ accumulation. Shikonin increased mitochondrial membrane depolarization and altered the levels of apoptosis-related proteins, with a decrease in B cell lymphoma (Bcl)-2 and an increase in Bcl-2-associated X protein, and subsequently, increased expression of cleaved forms of caspase-9 and -3. Taken together, we suggest that these mechanisms, including MAPK signaling and the ER-and mitochondria-mediated pathways, may underlie shikonin-induced apoptosis related to its anticancer effect.


Subject(s)
Apoptosis , bcl-2-Associated X Protein , Caspase 9 , Cell Death , Cell Line , Colon , Colonic Neoplasms , DNA Fragmentation , Endoplasmic Reticulum , Extracellular Vesicles , Humans , Inhibitory Concentration 50 , Lymphoma, B-Cell , Mitochondria , Mitochondrial Membranes , Protein Kinases
20.
Article in English | WPRIM | ID: wpr-719481

ABSTRACT

The Endoplasmic reticulum (ER), an indispensable sub-cellular component of the eukaryotic cell carries out essential functions, is critical to the survival of the organism. The chaperone proteins and the folding enzymes which are multi-domain ER effectors carry out 3-dimensional conformation of nascent polypeptides and check misfolded protein aggregation, easing the exit of functional proteins from the ER. Diverse conditions, for instance redox imbalance, alterations in ionic calcium levels, and inflammatory signaling can perturb the functioning of the ER, leading to a build-up of unfolded or misfolded proteins in the lumen. This results in ER stress, and aiming to reinstate protein homeostasis, a well conserved reaction called the unfolded protein response (UPR) is elicited. Equally, in protracted cellular stress or inadequate compensatory reaction, UPR pathway leads to cell loss. Dysfunctional ER mechanisms are responsible for neuronal degeneration in numerous human diseases, for instance Alzheimer's, Parkinson's and Huntington's diseases. In addition, mounting proof indicates that ER stress is incriminated in psychiatric diseases like major depressive disorder, bipolar disorder, and schizophrenia. Accumulating evidence suggests that pharmacological agents regulating the working of ER may have a role in diminishing advancing neuronal dysfunction in neuropsychiatric disorders. Here, new findings are examined which link the foremost mechanisms connecting ER stress and cell homeostasis. Furthermore, a supposed new pathogenic model of major neuropsychiatry disorders is provided, with ER stress proposed as the pivotal step in disease development.


Subject(s)
Apoptosis , Biological Psychiatry , Bipolar Disorder , Calcium , Depressive Disorder, Major , Endoplasmic Reticulum Stress , Endoplasmic Reticulum , Eukaryotic Cells , Homeostasis , Humans , Neurons , Neuropsychiatry , Oxidation-Reduction , Peptides , Proteostasis Deficiencies , Schizophrenia , Unfolded Protein Response
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