scholarly journals MFG-E8 Maintains Cellular Homeostasis by Suppressing Endoplasmic Reticulum Stress in Pancreatic Exocrine Acinar Cells

2022 ◽  
Vol 9 ◽  
Author(s):  
Yifan Ren ◽  
Wuming Liu ◽  
Jia Zhang ◽  
Jianbin Bi ◽  
Meng Fan ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Milk Fat ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Cellular Homeostasis ◽  
Pancreatic Exocrine

Excessive endoplasmic reticulum (ER) stress contributes significantly to the pathogenesis of exocrine acinar damage in acute pancreatitis. Our previous study found that milk fat globule EGF factor 8 (MFG-E8), a lipophilic glycoprotein, alleviates acinar cell damage during AP via binding to αvβ3/5 integrins. Ligand-dependent integrin-FAK activation of STAT3 was reported to be of great importance for maintaining cellular homeostasis. However, MFG-E8’s role in ER stress in pancreatic exocrine acinar cells has not been evaluated. To study this, thapsigargin, brefeldin A, tunicamycin and cerulein + LPS were used to induce ER stress in rat pancreatic acinar cells in vitro. L-arginine- and cerulein + LPS-induced acute pancreatitis in mice were used to study ER stress in vivo. The results showed that MFG-E8 dose-dependently inhibited ER stress under both in vitro and in vivo conditions. MFG-E8 knockout mice suffered more severe ER stress and greater inflammatory response after L-arginine administration. Mechanistically, MFG-E8 increased phosphorylation of FAK and STAT3 in cerulein + LPS-treated pancreatic acinar cells. The presence of specific inhibitors of αvβ3/5 integrin, FAK or STAT3 abolished MFG-E8’s effect on cerulein + LPS-induced ER stress in pancreatic acinar cells. In conclusion, MFG-E8 maintains cellular homeostasis by alleviating ER stress in pancreatic exocrine acinar cells.

scholarly journals Dehydrodiisoeugenol inhibits colorectal cancer growth by endoplasmic reticulum stress-induced autophagic pathways

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Changhong Li ◽  
Kui Zhang ◽  
Guangzhao Pan ◽  
Haoyan Ji ◽  
Chongyang Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Endoplasmic Reticulum ◽  
Cell Growth ◽  
Er Stress ◽  
Cancer Cells ◽  
Tumor Xenograft ◽  
Anticancer Activities ◽  
Colorectal Cancer Cells

Abstract Background Dehydrodiisoeugenol (DEH), a novel lignan component extracted from nutmeg, which is the seed of Myristica fragrans Houtt, displays noticeable anti-inflammatory and anti-allergic effects in digestive system diseases. However, the mechanism of its anticancer activity in gastrointestinal cancer remains to be investigated. Methods In this study, the anticancer effect of DEH on human colorectal cancer and its underlying mechanism were evaluated. Assays including MTT, EdU, Plate clone formation, Soft agar, Flow cytometry, Electron microscopy, Immunofluorescence and Western blotting were used in vitro. The CDX and PDX tumor xenograft models were used in vivo. Results Our findings indicated that treatment with DEH arrested the cell cycle of colorectal cancer cells at the G1/S phase, leading to significant inhibition in cell growth. Moreover, DEH induced strong cellular autophagy, which could be inhibited through autophagic inhibitors, with a rction in the DEH-induced inhibition of cell growth in colorectal cancer cells. Further analysis indicated that DEH also induced endoplasmic reticulum (ER) stress and subsequently stimulated autophagy through the activation of PERK/eIF2α and IRE1α/XBP-1 s/CHOP pathways. Knockdown of PERK or IRE1α significantly decreased DEH-induced autophagy and retrieved cell viability in cells treated with DEH. Furthermore, DEH also exhibited significant anticancer activities in the CDX- and PDX-models. Conclusions Collectively, our studies strongly suggest that DEH might be a potential anticancer agent against colorectal cancer by activating ER stress-induced inhibition of autophagy.

scholarly journals Biochanin A Alleviates Cerebral Ischemia/Reperfusion Injury by Suppressing Endoplasmic Reticulum Stress-Induced Apoptosis and p38MAPK Signaling Pathway In Vivo and In Vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Min-min Guo ◽  
Sheng-biao Qu ◽  
Hui-ling Lu ◽  
Wen-bo Wang ◽  
Mu-Liang He ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
P38 Mapk ◽  
Ischemia Reperfusion ◽  
Biochanin A ◽  
Neurological Deficits ◽  
Mapk Phosphorylation ◽  
Cerebral Ischemia Reperfusion

We have previously shown that biochanin A exhibits neuroprotective properties in the context of cerebral ischemia/reperfusion (I/R) injury. The mechanistic basis for such properties, however, remains poorly understood. This study was therefore designed to explore the manner whereby biochanin A controls endoplasmic reticulum (ER) stress, apoptosis, and inflammation within fetal rat primary cortical neurons in response to oxygen-glucose deprivation/reoxygenation (OGD/R) injury, and in a rat model of middle cerebral artery occlusion and reperfusion (MCAO/R) injury. For the OGD/R in vitro model system, cells were evaluated after a 2 h OGD following a 24 h reoxygenation period, whereas in vivo neurological deficits were evaluated following 2 h of ischemia and 24 h of reperfusion. The expression of proteins associated with apoptosis, ER stress (ERS), and p38 MAPK phosphorylation was evaluated in these samples. Rats treated with biochanin A exhibited reduced neurological deficits relative to control rats following MCAO/R injury. Additionally, GRP78 and CHOP levels rose following I/R modeling both in vitro and in vivo, whereas biochanin A treatment was associated with reductions in CHOP levels but further increases in GRP78 levels. In addition, OGD/R or MCAO/R were associated with markedly enhanced p38 MAPK phosphorylation that was alleviated by biochanin A treatment. Similarly, OGD/R or MCAO/R injury resulted in increases in caspase-3, caspase-12, and Bax levels as well as decreases in Bcl-2 levels, whereas biochanin A treatment was sufficient to reverse these phenotypes. Together, these findings thus demonstrate that biochanin A can alleviate cerebral I/R-induced damage at least in part via suppressing apoptosis, ER stress, and p38 MAPK signaling, thereby serving as a potent neuroprotective agent.

scholarly journals Regulation of Adipsin Expression by Endoplasmic Reticulum Stress in Adipocytes

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 314
Author(s):  
Ka-Young Ryu ◽  
Eon Ju Jeon ◽  
Jaechan Leem ◽  
Jae-Hyung Park ◽  
Hochan Cho
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Peroxisome Proliferator ◽  
Adipose Tissues ◽  
Peroxisome Proliferator Activated Receptor ◽  
Er Stress Response ◽  
Stress Markers ◽  
Transcriptional Reprogramming

Adpsin is an adipokine that stimulates insulin secretion from β-cells and improves glucose tolerance. Its expression has been found to be markedly reduced in obese animals. However, it remains unclear what factors lead to downregulation of adipsin in the context of obesity. Endoplasmic reticulum (ER) stress response is activated in various tissues under obesity-related conditions and can induce transcriptional reprogramming. Therefore, we aimed to investigate the relationship between adipsin expression and ER stress in adipose tissues during obesity. We observed that obese mice exhibited decreased levels of adipsin in adipose tissues and serum and increased ER stress markers in adipose tissues compared to lean mice. We also found that ER stress suppressed adipsin expression via adipocytes-intrinsic mechanisms. Moreover, the ER stress-mediated downregulation of adipsin was at least partially attributed to decreased expression of peroxisome proliferator-activated receptor γ (PPARγ), a key transcription factor in the regulation of adipocyte function. Finally, treatment with chemical chaperones recovered the ER stress-mediated downregulation of adipsin and PPARγ in vivo and in vitro. Our findings suggest that activated ER stress in adipose tissues is an important cause of the suppression of adipsin expression in the context of obesity.

scholarly journals Morphometric Measurements to Quantify the Cerulein Induced Hyperstimulatory Pancreatitis of Rats under the Protective Effect of Lectins

1998 ◽  
Vol 17 (4) ◽  
pp. 219-230 ◽  
Author(s):  
Ludwig Jonas ◽  
Ulrike Mikkat ◽  
Anke Witte ◽  
Uta Beckmann ◽  
Katrin Dölker ◽  
...  
Keyword(s):  
Protective Effect ◽  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Ulex Europaeus ◽  
Serum Amylase Activity

In preceding papers we demonstrated an inhibitory effect of wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA) on the cholecystokinin (CCK) binding to the CCK receptor of rat pancreatic cells and also on the CCK induced Ca2+release and α-amylase secretionin vitroas well as on pancreatic secretion of intact ratsin vivo. In the present study we show the same inhibitory effect of both lectins on the cerulein pancreatitis of rats. This acute pancreatitis was induced by supramaximal injections (5 µg/kg/h iv or 10 µg/kg/h ip) of the CCK analogue cerulein in rats every hour. To monitor the degree of pancreatitis, we measured the number and diameter of injury vacuoles in the pancreatic acinar cells as one of the most important signs of this type of pancreatitis by light microscopic morphometry with two different systems on paraffin sections. Furthermore, the serum α-amylase activity was measured biochemically. We found a correlation between the diameter of vacuoles inside the acinar cells and the serum enzyme activity up to 24 h. The simultaneous ip administration of cerulein and WGA or UEA in a dosage of 125 µg/kg/h for 8 h led to a reduction of vacuolar diameter from 13.1 ± 2.0 µm (cerulein) to 7.5 ± 1.1 µm (cerulein + WGA) or 7.2 ± 1.3 µm (cerulein + UEA). The serum amylase activity was reduced from 63.7 ± 15.8 mmol/l \times min (cerulein) to 37.7 ± 11.8 (cerulein + WGA) or 39.4; +52.9; -31.1 (cerulein + UEA-I). Both parameters allow the grading this special type of pancreatitis to demonstrate the protective effect of the lectins.

scholarly journals A Novel Transcription Factor, ERD15 (Early Responsive to Dehydration 15), Connects Endoplasmic Reticulum Stress with an Osmotic Stress-induced Cell Death Signal

2011 ◽  
Vol 286 (22) ◽  
pp. 20020-20030 ◽  
Author(s):  
Murilo S. Alves ◽  
Pedro A. B. Reis ◽  
Silvana P. Dadalto ◽  
Jerusa A. Q. A. Faria ◽  
Elizabeth P. B. Fontes ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Er Stress ◽  
Unfolded Protein ◽  
Eukaryotic Organisms ◽  
Protein Response

As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

scholarly journals Upregulation of dynamin II expression during the acquisition of a mature pancreatic acinar cell phenotype.

1996 ◽  
Vol 44 (12) ◽  
pp. 1373-1378 ◽  
Author(s):  
T A Cook ◽  
K J Mesa ◽  
B A Gebelein ◽  
R A Urrutia
Keyword(s):  
Acinar Cell ◽  
Growth Factor Receptor ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Cell Phenotype ◽  
Receptor Mediated Endocytosis ◽  
Ar42j Cells

Members of the dynamin superfamily are GTPases which have been shown to support receptor-mediated endocytosis in vivo and bind to growth factor receptor-associated proteins in vitro. In acinar cells of the pancreas, receptor-mediated endocytosis is very important for the recycling of membranes after secretory granule release. Therefore, characterization of the molecular machinery responsible for this process is critical for a better understanding of this phenomenon. In this study we sought to determine the expression pattern of the endocytic GTPase dynamin II during pancreatic acinar cell differentiation in developing rat embryos and in dexamethasone-treated AR42J cells using Western blot, Northern blot, and immunocytochemical analyses. During pancreatic development, dynamin immunoreactivity is almost undetectable until day E17 but undergoes significant upregulation in acinar cells starting at E18. In addition, the levels of dynamin mRNA and protein in AR42J cells increase approximately threefold during dexamethasone-induced acinar differentiation. The increase in dynamin levels that occurs in both embryonic pancreatic cells and dexamethasone-treated AR42J cells correlates with the establishment of a more differentiated acinar phenotype. Therefore, these results suggest a potential role for dynamin in supporting receptor-mediated endocytosis in mature pancreatic acinar cells.

Abstract 13: Targeting the PERK Pathway of ER Stress Response for Endothelium Protection and Restenosis Prevention: A Paradigm for Developing Anti-thrombogenic Stents

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Bowen Wang ◽  
Mengxue Zhang ◽  
Xudong Shi ◽  
Lian-Wang Guo ◽  
Michael Hoffmann ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Selective Inhibition ◽  
Post Injury ◽  
Mortality And Morbidity ◽  
Lumen Narrowing ◽  
Potential Strategy ◽  
Differentiation And Proliferation

Introduction: Cardiovascular disease is the leading cause of mortality and morbidity in the US. Reconstructions often fail due to the recurrent lumen narrowing, or restenosis. Stents eluting rapamycin or paclitaxel are deployed to inhibit the excessive proliferation of smooth muscle cells (SMCs), which is the core component of restenosis. However, these drugs cause collateral damage to endothelial cells (ECs) leading to stent thrombosis. To address this, our group initiated the first campaign of drug screening for compounds that selectively inhibit SMC proliferation without causing EC dysfunction. We recently identified lead compounds as such, which are inhibitors for protein kinase RNA-like endoplasmic reticulum kinase (PERK), an endoplasmic reticulum (ER) stress sensor. Here we evaluated PERK as a target for intervention of both SMC pathophysiology and EC dysfunction. Methods: Rat carotid artery balloon angioplasty was performed as a restenosis model. PDGF-BB and TNF-a were applied to primary human aortic SMCs and ECs, respectively, to mimic the in vivo pathogenic stimuli. Results: In balloon-injured arteries, both PERK phosphorylation and the expression of its downstream transcription factor ATF4 were increased compared to sham control. PERK activation was also observed in vitro in both SMCs and ECs stimulated with PDGF-BB and TNF-a, respectively. In SMCs, either selective inhibition (1μM GSK2606414) or siRNA knockdown of PERK abolished PDGF-BB induced de-differentiation and proliferation. In ECs, PERK antagonism abrogated TNF-a induced growth impairment and EC secretion of Tissue Factor (TF), which is the key initiator of thrombogenesis. Finally, in a pilot experiment, peri-adventitial application of GSK2606414 (25mg/kg, n=2 rats) reduced intima/media ratio by 80% and increased lumen area by ~ 2 fold compared to vehicle control (n=2) at 4 weeks post injury. Conclusion: Our results indicate an important role of PERK activation in promoting SMC phenotype switching and EC dysfunction in vitro as well as restenosis in vivo . Thus, PERK targeting represents a potential strategy to simultaneously achieve restenosis prevention and endothelium protection, with a long-term goal of developing anti-thrombogenic drug-eluting stents.

Tauroursodeoxycholic acid reduces endoplasmic reticulum stress, acinar cell damage, and systemic inflammation in acute pancreatitis

2011 ◽  
Vol 301 (5) ◽  
pp. G773-G782 ◽  
Author(s):  
Ersin Seyhun ◽  
Antje Malo ◽  
Claus Schäfer ◽  
Christopher A. Moskaluk ◽  
Ralf-Thorsten Hoffmann ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Stress Responses ◽  
Cell Damage ◽  
Binding Protein ◽  
Edema Formation ◽  
Tauroursodeoxycholic Acid ◽  
Caspase 12

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.

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