EPA and DHA confer protection against DON-induced endoplasmic reticulum stress and iron imbalance in IPEC-1 cells

2021 ◽  
pp. 1-29
Author(s):  
Jia Lin ◽  
Feifei Huang ◽  
Tianzeng Liang ◽  
Qin Qin ◽  
Qiao Xu ◽  
...  

Abstract This study assessed the molecular mechanism of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) protection against IPEC-1 cell damage induced by deoxynivalenol (DON). The cells were divided into six groups, including the CON group, the EPA group, the DHA group, the DON group, the EPA+DON group, and the DHA+DON group. RNA sequencing was used to investigate the potential mechanism, and qRT-PCR was employed to verify the expression of selected genes. Changes in ultrastructure were used to estimate pathological changes and endoplasmic reticulum (ER) injury in IPEC-1 cells. Transferrin receptor 1 (TFR1) was tested by ELISA. Fe2+ and malondialdehyde (MDA) contents were estimated by spectrophotometry, and reactive oxygen species (ROS) was assayed by fluorospectrophotometry. RNA sequencing analysis showed that EPA and DHA had a significant effect on the expression of genes involved in ER stress and iron balance during DON-induced cell injury. The results showed that DON increased ER damage, the content of MDA and ROS, the ratio of X-box binding protein 1s (XBP-1s)/X-box binding protein 1u (XBP-1u), the concentration of Fe2+, and the activity of TFR1. However, the results also showed that EPA and DHA decreased the ratio of XBP-1s/XBP-1u to relieve DON-induced ER damage of IPEC-1 cells. Moreover, EPA and DHA (especially DHA) reversed the factors related to iron balance. It can be concluded that EPA and DHA reversed IPEC-1 cell damage induced by DON. DHA has the potential to protect IPEC-1 cells from DON-induced iron imbalance by inhibiting ER stress.

2011 ◽  
Vol 301 (5) ◽  
pp. G773-G782 ◽  
Author(s):  
Ersin Seyhun ◽  
Antje Malo ◽  
Claus Schäfer ◽  
Christopher A. Moskaluk ◽  
Ralf-Thorsten Hoffmann ◽  
...  

In acute pancreatitis, endoplasmic reticulum (ER) stress prompts an accumulation of malfolded proteins inside the ER, initiating the unfolded protein response (UPR). Because the ER chaperone tauroursodeoxycholic acid (TUDCA) is known to inhibit the UPR in vitro, this study examined the in vivo effects of TUDCA in an acute experimental pancreatitis model. Acute pancreatitis was induced in Wistar rats using caerulein, with or without prior TUDCA treatment. UPR components were analyzed, including chaperone binding protein (BiP), phosphorylated protein kinase-like ER kinase (pPERK), X-box binding protein (XBP)-1, phosphorylated c-Jun NH2-terminal kinase (pJNK), CCAAT/enhancer binding protein homologues protein, and caspase 12 and 3 activation. In addition, pancreatitis biomarkers were measured, such as serum amylase, trypsin activation, edema formation, histology, and the inflammatory reaction in pancreatic and lung tissue. TUDCA treatment reduced intracellular trypsin activation, edema formation, and cell damage, while leaving amylase levels unaltered. The activation of myeloperoxidase was clearly reduced in pancreas and lung. Furthermore, TUDCA prevented caerulein-induced BiP upregulation, reduced XBP-1 splicing, and caspase 12 and 3 activation. It accelerated the downregulation of pJNK. In controls without pancreatitis, TUDCA showed cytoprotective effects including pPERK signaling and activation of downstream targets. We concluded that ER stress responses activated in acute pancreatitis are grossly attenuated by TUDCA. The chaperone reduced the UPR and inhibited ER stress-associated proapoptotic pathways. TUDCA has a cytoprotective potential in the exocrine pancreas. These data hint at new perspectives for an employment of chemical chaperones, such as TUDCA, in prevention of acute pancreatitis.


2011 ◽  
Vol 437 (3) ◽  
pp. 469-475 ◽  
Author(s):  
Sonia Gallego-Sandín ◽  
María Teresa Alonso ◽  
Javier García-Sancho

CALHM1 (calcium homoeostasis modulator 1), a membrane protein with similarity to NMDA (N-methyl-D-aspartate) receptor channels that localizes in the plasma membrane and the ER (endoplasmic reticulum) of neurons, has been shown to generate a plasma-membrane Ca2+ conductance and has been proposed to influence Alzheimer's disease risk. In the present study we have investigated the effects of CALHM1 on intracellular Ca2+ handling in HEK-293T [HEK (human embryonic kidney)-293 cells expressing the large T-antigen of SV40 (simian virus 40)] cells by using targeted aequorins for selective monitorization of Ca2+ transport by organelles. We find that CALHM1 increases Ca2+ leak from the ER and, more importantly, reduces ER Ca2+ uptake by decreasing both the transport capacity and the Ca2+ affinity of SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase). As a result, the Ca2+ content of the ER is drastically decreased. This reduction in the Ca2+ content of the ER triggered the UPR (unfolded protein response) with induction of several ER stress markers, such as CHOP [C/EBP (CCAAT/enhancer-binding protein)-homologous protein], ERdj4, GRP78 (glucose-regulated protein of 78 kDa) and XBP1 (X-box-binding protein 1). Thus CALHM1 might provide a relevant link between Ca2+ homoeostasis disruption, ER stress and cell damage in the pathogenesis of neurodegenerative diseases


2019 ◽  
Vol 16 (1) ◽  
pp. 3-11
Author(s):  
Luisa Halbe ◽  
Abdelhaq Rami

Introduction: Endoplasmic reticulum (ER) stress induced the mobilization of two protein breakdown routes, the proteasomal- and autophagy-associated degradation. During ERassociated degradation, unfolded ER proteins are translocated to the cytosol where they are cleaved by the proteasome. When the accumulation of misfolded or unfolded proteins excels the ER capacity, autophagy can be activated in order to undertake the degradative machinery and to attenuate the ER stress. Autophagy is a mechanism by which macromolecules and defective organelles are included in autophagosomes and delivered to lysosomes for degradation and recycling of bioenergetics substrate. Materials and Methods: Autophagy upon ER stress serves initially as a protective mechanism, however when the stress is more pronounced the autophagic response will trigger cell death. Because autophagy could function as a double edged sword in cell viability, we examined the effects autophagy modulation on ER stress-induced cell death in HT22 murine hippocampal neuronal cells. We investigated the effects of both autophagy-inhibition by 3-methyladenine (3-MA) and autophagy-activation by trehalose on ER-stress induced damage in hippocampal HT22 neurons. We evaluated the expression of ER stress- and autophagy-sensors as well as the neuronal viability. Results and Conclusion: Based on our findings, we conclude that under ER-stress conditions, inhibition of autophagy exacerbates cell damage and induction of autophagy by trehalose failed to be neuroprotective.


Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
Jing Zhang ◽  
Xin Xu ◽  
Yan Liu ◽  
Lin Zhang ◽  
Jack Odle ◽  
...  

This study was conducted to elucidate the biological effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cell proliferation, differentiation and gene expression in C2C12 myoblasts. C2C12 were treated with various concentrations of EPA or DHA under proliferation and differentiation conditions. Cell viability was analyzed using cell counting kit-8 assays (CCK-8). The Edu assays were performed to analyze cell proliferation. To analyze cell differentiation, the expressions of myogenic marker genes were determined at the transcriptional and translational levels by qRT-PCR, immunoblotting and immunofluorescence. Global gene expression patterns were characterized using RNA-sequencing. Phosphorylation levels of ERK and Akt were examined by immunoblotting. Cell viability and proliferation was significantly inhibited after incubation with EPA (50 and 100 μM) or DHA (100 μM). Both EPA and DHA suppressed C2C12 myoblasts differentiation. RNA-sequencing analysis revealed that some muscle-related genes were significantly downregulated following EPA or DHA (50 μM) treatment, including insulin-like growth factor 2 (IGF-2), troponin T3 (Tnnt3), myoglobin (Mb), myosin light chain phosphorylatable fast skeletal muscle (Mylpf) and myosin heavy polypeptide 3 (Myh3). IGF-2 was crucial for the growth and differentiation of skeletal muscle and could activate the PI3K/Akt and the MAPK/ERK cascade. We found that EPA and DHA (50 μM) decreased the phosphorylation levels of ERK1/2 and Akt in C2C12 myoblasts. Thus, this study suggested that EPA and DHA exerted an inhibitory effect on myoblast proliferation and differentiation and downregulated muscle-related genes expression.


2020 ◽  
Vol 48 (9) ◽  
pp. 030006052094976
Author(s):  
Min Li ◽  
Ying Zhang ◽  
Jixing Wang

Objective Sepsis-associated encephalopathy (SAE) is a common complication of sepsis, and excessive endoplasmic reticulum (ER) stress is closely correlated with the cell injury caused by sepsis. This study aimed to analyze the possible role of ER stress in SAE cell models. Methods PC12 and MES23.5 cells were treated with increasing concentrations of lipopolysaccharides (LPS). The Cell Counting Kit-8 assay was used to detect cell viability and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed to assess cell apoptosis. In addition, the protein expression levels of ER stress markers [GRP78, CHOP, inositol-requiring enzyme 1 (IRE1), and PKR-like ER kinase (PERK)] and apoptosis-related proteins (Bax, Bcl-2, caspase-3, and cleaved caspase-3) were analyzed using western blotting. Results LPS treatment activated ER stress markers in both the PC12 and MES23.5 cells. The overexpression of GRP78 significantly reduced cell viability and enhanced cell apoptosis in a time-dependent manner. An ER stress inhibitor, 4-PBA, significantly enhanced cell viability and inhibited the cell apoptosis induced by LPS. Therefore, an enhanced unfolded protein response (UPR) and UPR suppression may regulate cell apoptosis. Conclusions UPR was shown to be involved in regulating LPS-induced neuron injury. UPR could be a potential therapeutic target in SAE.


2020 ◽  
Author(s):  
Dong Im Kim ◽  
Mi-Kyung Song ◽  
Kyuhong Lee

Abstract Background Exposure to particular matter (PM)2.5, including diesel exhaust particulates (DEP), has adverse effects on the respiratory system. Endoplasmic reticulum (ER) abnormalities contribute to respiratory disease pathogenesis such as lung inflammation. However, there is little published research on the relationship between DEP exposure and ER stress in the respiratory immune system and especially the alveolar macrophages (AM). Here, we examined ER stress and inflammatory responses in a DEP-induced murine lung inflammation model and in DEP-stimulated AM.Results DEP treatment increased relative lung weight and the number of total cells, neutrophils, and lymphocytes in mouse BALF. Histological examinations also showed that DEP exposure induced neutrophilic lung inflammation and increased the number of DEP-pigmented AM. Western blot analysis showed that BiP and CHOP were relatively upregulated in DEP-induced mouse lung tissues. DEP caused cell damage, increased intracellular reactive oxygen species (ROS), and upregulated the genes associated with inflammation (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, interferon-γ, and toll-like receptor 4) and with ER stress (bound immunoglobulin protein [BiP], CCAAT/enhancer binding protein-homologous protein [CHOP], sXBP-1, and activating transcription factor 4) in AM. Furthermore, DEP stimulation upregulated the gene encoding the chemokine CXCL1/KC in AM.Conclusions DEP may contribute to neutrophilic lung inflammation pathogenesis by modulating ER stress-mediated CXCL1/KC expression in alveolar macrophages.


2020 ◽  
Vol 36 (12) ◽  
pp. 1002-1009
Author(s):  
Ke Gao ◽  
Chengfei Zhang ◽  
Yihong Tian ◽  
Sajid Naeem ◽  
Yingmei Zhang ◽  
...  

It is well-documented that lead (Pb) toxicity can affect almost all systems in living organisms. It can induce selective autophagy of mitochondria (mitophagy) by triggering reactive oxygen species production. Emerging evidence has suggested that Pb-induced autophagy can also be activated by the endoplasmic reticulum (ER) stress pathway. However, the interplay between ER stress and mitophagy remains to be elucidated. In this study, human embryonic kidney HEK293 cells were employed to investigate the role of ER stress in Pb-induced mitophagy. The results showed that the cell viability was decreased and cell damage was induced after exposure to Pb (0, 0.5, 1, 2, and 4 mM) for 24 h in a dose-dependent manner. Moreover, the expression of LC3-Ⅱ was significantly increased, and the expression of HSP60 was dramatically decreased after exposure to 1 mM and 2 mM Pb, indicating the induction of mitophagy following Pb exposure. Meanwhile, the expressions of activating transcription factor 6, inositol-requiring protein-1α, CCAAT/enhancer binding protein homologous protein, and glucose-regulated protein 78 were dramatically increased after Pb treatment, signifying the initiation of ER stress. Notably, the mitophagic effect was significantly compromised when ER stress was inhibited by 0.5 mM 4-phenylbutyrate, which was evidenced by lesser decreases in HSP60 expression and level of LC3-Ⅱ, suggesting Pb-induced mitophagy may be activated by the ER stress. Taken together, these findings provide a better understanding of Pb toxicity and suggest that Pb-induced ER stress may play a regulatory role in the upstream of mitophagy.


2010 ◽  
Vol 31 (4) ◽  
pp. 605-605
Author(s):  
Susana Granell ◽  
Sameer Mohammad ◽  
Ramanagouda Ramanagoudr-Bhojappa ◽  
Giulia Baldini

Abstract Melanocortin-4 receptor (MC4R) is a G protein-coupled receptor expressed in the brain where it controls food intake. Many obesity-linked MC4R variants are poorly expressed at the plasma membrane and are retained intracellularly. We have studied the intracellular localization of four obesity-linked MC4R variants, P78L, R165W, I316S, and I317T, in immortalized neurons. We find that these variants are all retained in the endoplasmic reticulum (ER), are ubiquitinated to a greater extent than the wild-type (wt) receptor, and induce ER stress with increased levels of ER chaperones as compared with wt-MC4R and appearance of CCAAT/enhancer-binding protein homologous protein. Expression of the X-box-binding-protein-1 with selective activation of a protective branch of the unfolded protein response did not have any effect on the cell surface expression of MC4R-I316S. Conversely, the pharmacological chaperone 4-phenyl butyric acid (PBA) increased the cell surface expression of wt-MC4R, MC4R-I316S, and I317T by more than 40%. PBA decreased ubiquitination of MC4R-I316S and prevented ER stress induced by expression of the mutant, suggesting that the drug functions to promote MC4R folding. MC4R-I316S rescued to the cell surface is functional, with a 52% increase in agonist-induced cAMP production, as compared with untreated cells. Also direct inhibition of wt-MC4R and MC4R-I316S ubiquitination by a specific inhibitor of the ubiquitin-activating enzyme 1 increased by approximately 40% the expression of the receptors at the cell surface, and the effects of PBA and ubiquitin-activating enzyme 1 were additive. These data offer a cell-based rationale that drugs that improve MC4R folding or decrease ER-associated degradation of the receptor may function to treat some forms of hereditary obesity.


Author(s):  
Meixue Chen ◽  
Jing Li ◽  
Jinfeng Wang ◽  
Yuan Le ◽  
Chunfeng Liu

Abstract Sepsis-induced cardiomyopathy (SIC) is a major complication of sepsis. SET and MYND domain containing 1 (SMYD1) has central importance in heart development, and its role in SIC has not been identified. Herein, we found that the expression of SMYD1 was downregulated in myocardial tissues of SIC patients (from GEO database: GSE79962) and lipopolysaccharide (LPS)-induced SIC rats, and LPS-induced H9c2 cardiomyocytes. We used LPS-stimulated H9c2 cells that mimic sepsis in vitro to explore the function of SMYD1 in SIC. MTT assay, LDH and CK-MB release assay, flow cytometry, and ELISA assay showed that SMYD1 overexpression enhanced cell viability, alleviated cell injury, impeded apoptosis, and reduced the level of pro-inflammatory factors and NF-κB activation under the condition of LPS stimulation. Moreover, SMYD1 exerted protective effect on H9c2 cells stimulated with LPS through relieving endoplasmic reticulum (ER) stress. In conclusion, overexpression of SMYD1 alleviates cardiac injury through relieving ER stress during sepsis.


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