scholarly journals Development of a Rapid in vivo Assay to Evaluate the Efficacy of IRE1-specific Inhibitors of the Unfolded Protein Response Using Medaka Fish

2019 ◽  
Vol 45 (1) ◽  
pp. 23-31
Author(s):  
Byungseok Jin ◽  
Tokiro Ishikawa ◽  
Mai Taniguchi ◽  
Satoshi Ninagawa ◽  
Tetsuya Okada ◽  
...  
Keyword(s):  
Unfolded Protein Response ◽  
Medaka Fish ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
Specific Inhibitors

scholarly journals Transcriptome Analysis of Recombinant Protein Secretion by Aspergillus nidulans and the Unfolded-Protein Response In Vivo

2005 ◽  
Vol 71 (5) ◽  
pp. 2737-2747 ◽  
Author(s):  
Andrew H. Sims ◽  
Manda E. Gent ◽  
Karin Lanthaler ◽  
Nigel S. Dunn-Coleman ◽  
Stephen G. Oliver ◽  
...  
Keyword(s):  
Gene Expression ◽  
Recombinant Protein ◽  
Unfolded Protein Response ◽  
Aspergillus Nidulans ◽  
Filamentous Fungi ◽  
Protein Secretion ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

ABSTRACT Filamentous fungi have a high capacity for producing large amounts of secreted proteins, a property that has been exploited for commercial production of recombinant proteins. However, the secretory pathway, which is key to the production of extracellular proteins, is rather poorly characterized in filamentous fungi compared to yeast. We report the effects of recombinant protein secretion on gene expression levels in Aspergillus nidulans by directly comparing a bovine chymosin-producing strain with its parental wild-type strain in continuous culture by using expressed sequence tag microarrays. This approach demonstrated more subtle and specific changes in gene expression than those observed when mimicking the effects of protein overproduction by using a secretion blocker. The impact of overexpressing a secreted recombinant protein more closely resembles the unfolded-protein response in vivo.

scholarly journals Enforced dimerization between XBP1s and ATF6f enhances the protective effects of the unfolded protein response (UPR) in models of neurodegeneration

2020 ◽  
Author(s):  
René L. Vidal ◽  
Denisse Sepulveda ◽  
Paulina Troncoso-Escudero ◽  
Paula Garcia-Huerta ◽  
Constanza Gonzalez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Unfolded Protein Response ◽  
Target Genes ◽  
Cell Function ◽  
Alpha Synuclein ◽  
Protective Effects ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

AbstractAlteration to endoplasmic reticulum (ER) proteostasis is observed on a variety of neurodegenerative diseases associated with abnormal protein aggregation. Activation of the unfolded protein response (UPR) enables an adaptive reaction to recover ER proteostasis and cell function. The UPR is initiated by specialized stress sensors that engage gene expression programs through the concerted action of the transcription factors ATF4, ATF6f, and XBP1s. Although UPR signaling is generally studied as unique linear signaling branches, correlative evidence suggests that ATF6f and XBP1s may physically interact to regulate a subset of UPR-target genes. Here, we designed an ATF6f-XBP1s fusion protein termed UPRplus that behaves as a heterodimer in terms of its selective transcriptional activity. Cell-based studies demonstrated that UPRplus has stronger an effect in reducing the abnormal aggregation of mutant huntingtin and alpha-synuclein when compared to XBP1s or ATF6 alone. We developed a gene transfer approach to deliver UPRplus into the brain using adeno-associated viruses (AAVs) and demonstrated potent neuroprotection in vivo in preclinical models of Parkinson’s and Huntington’s disease. These results support the concept where directing UPR-mediated gene expression toward specific adaptive programs may serve as a possible strategy to optimize the beneficial effects of the pathway in different disease conditions.

scholarly journals Hmga2 Functions As an Oncogene upon the Deletion of Tet2 and Promotes the Pathogenesis of Myelodysplastic Syndrome

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3782-3782
Author(s):  
Jie Bai ◽  
Sho Kubota ◽  
Takako Yokomizo ◽  
Akinori Kanai ◽  
Yuqi Sun ◽  
...  
Keyword(s):  
Myelodysplastic Syndrome ◽  
Unfolded Protein Response ◽  
Binding Sites ◽  
Disease Stage ◽  
Wild Type ◽  
Transcriptional Program ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

High Mobility Group AT-hook 2 (HMGA2) is a chromatin modifier and its overexpression has been found in a subset of patients with myelodysplastic syndrome (MDS). The high level of HMGA2 expression appears to predict poor prognosis in various tumors; however, it remains unclear how HMGA2 dysregulates expression of target genes to facilitate the transformation. To elucidate the mechanisms by which the overexpression of Hmga2 promotes the development of MDS, we generated an Hmga2-expressing Tet2-deficient (Hmga2-Tet2Δ/Δ) mouse model showing the progressive phenotype of MDS. We found that Hmga2-Tet2Δ/Δ mice had neutropenia and anemia, but variable platelet counts, accompanied by elevated frequencies of mutant cells in myeloid cells. Hmga2-Tet2Δ/Δ mice showed a similar median survival to Tet2Δ/Δ mice (274 days vs 290 days), but shorter survival than Hmga2-Tet2wt/wt mice (274 days vs undetermined). Moribund Hmga2-Tet2Δ/Δ mice showed progressive leukopenia and anemia, accompanied by the emergence of dysplastic neutrophils, myeloblasts and anisocytosis in the PB and BM and dysplastic megakaryocytes in the BM. Hmga2-Tet2Δ/Δ mice had mildly increased spleen weights, and expanded myeloid cells and HSPCs in the spleen without the deposition of fibrosis. During a 12-month observation, we found that Hmga2-Tet2Δ/Δ mice developed lethal MDS/MPN overlap disease (47%), MDS (33%), MPN (13%), and AML (7%), while 6 out of 11 Tet2Δ/Δ mice developed MPN (55%). Hmga2-Tet2wt/wt mice subsequently showed similar blood counts in PB and died without the expansion of leukemic or dysplastic blood cells. Therefore, Hmga2 overexpression did not transform wild-type HSCs but promoted the development of MDS in the absence of Tet2 in vivo. In order to elucidate the molecular mechanisms underlying the transformation of Hmga2-Tet2Δ/Δ cells, we initially performed gene expression profiling by a RNA sequencing analysis in LSK HSPCs isolated from WT, Hmga2-Tet2wt/wt, Tet2Δ/Δ, and Hmga2-Tet2Δ/Δ mice at a pre-disease stage and those isolated from two Hmga2-Tet2Δ/Δ MDS/MPN and AML mice. Hmga2-Tet2Δ/Δ leukemic cells were placed closer to one out of two Hmga2-Tet2Δ/Δ cells at the pre-disease stage, but clearly apart from the other genotype cells, indicating that Hmga2 overexpression and Tet2 loss result in the accumulation of alterations in the transcriptional program during the development of MDS.In order to clarify the mechanisms by which the overexpression of Hmga2 alters the transcriptional program in Tet2-deficient cells, we performed the ChIP-sequencing of FLAG-tagged Hmga2 in bone marrow progenitor cells isolated from WT, Hmga2-Tet2wt/wt, and Hmga2-Tet2Δ/Δ mice. The numbers of Hmga2-binding peaks were markedly lower in Tet2-deficient cells than in Hmga2-Tet2wt/wt cells (2227 peaks versus 11500 peaks). Furthermore, annotated genes adjacent to Hmga2-binding sites partially overlapped in both genotype cells, whereas 2965 out of 3843 genes identified in Tet2 wild-type cells lost the binding peaks of Hmga2 upon the deletion of Tet2. Based on the DNA-binding capacity of Hmga2, the loss of Tet2 remodeled the binding sites of Hmga2 via change in DNA methylation in Hmga2-binding flanking regions, which were not observed in the presence of Tet2, leading to significant enrichments in genes involved in cell-to-cell adhesion and cell morphogenesis in Hmga2-Tet2Δ/Δ cells. Furthermore, we found that the overexpression of Hmga2 and loss of Tet2 resulted in the activation of oncogenic pathways (e.g. TGF-b, TNF-a), but suppressed the expression of genes in the unfolded protein response. Notably, the inhibition of bile acid metabolism to reactivate the unfolded protein response markedly attenuated the proliferation of Hmga2-Tet2Δ/Δ cells. These combinatory effects on the transcriptional program and cellular functions were not redundant to those in either single mutant cell, supporting Hmga2 being a proto-oncogene because its overexpression alone was not sufficient to develop MDS in vivo. Thus, Hmga2 overexpression exerts synergistic, but also gain-of-function effects with the loss of Tet2 to target these key biological pathways and promotes the transformation of Tet2-deficient stem cells. This study also provides a new rationale for targeting the unfolded protein response in MDS cells expressing HMGA2. Disclosures No relevant conflicts of interest to declare.

scholarly journals USP19 deubiquitinating enzyme inhibits muscle cell differentiation by suppressing unfolded-protein response signaling

2015 ◽  
Vol 26 (5) ◽  
pp. 913-923 ◽  
Author(s):  
Benjamin Wiles ◽  
Miao Miao ◽  
Erin Coyne ◽  
Louise Larose ◽  
Andrey V. Cybulsky ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Unfolded Protein Response ◽  
Muscle Cell ◽  
Deubiquitinating Enzyme ◽  
Muscle Cell Differentiation ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

USP19 deubiquitinating enzyme has two isoforms, cytoplasmic and endoplasmic reticulum (ER) localized. The ER-localized isoform specifically suppresses muscle cell differentiation in vitro and appears to do so by inhibiting the unfolded-protein response that occurs during such differentiation. In vivo, loss of USP19 promotes muscle regeneration following injury.

scholarly journals Activation of the Unfolded Protein Response with the First-in-Class P97 Inhibitor CB-5083 Induces Stable Disease Regression and Overcomes Ara-C Resistance in AML

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1350-1350
Author(s):  
Steffan T. Nawrocki ◽  
Yingchun Han ◽  
Ronan LE Moigne ◽  
Valeria Visconte ◽  
Bartlomiej Przychodzen ◽  
...  
Keyword(s):  
Unfolded Protein Response ◽  
Board Of Directors ◽  
Cell Lines ◽  
Primary Cells ◽  
Advisory Committees ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

Abstract Acute myeloid leukemia (AML) therapy has remained relatively unchanged for more than 40 years with the majority of patients not achieving long-term remission when treated with currently available agents. Novel strategies are urgently needed to improve outcomes. The constitutive dysregulation of protein synthesis/turnover contributes to disease progression and drug resistance in many forms of cancer including AML. p97 (VCP) is a master regulator of protein turnover that has been implicated in oncogenesis and malignant pathogenesis. CB-5083 is a first-in-class selective and potent orally available inhibitor of p97 that in currently being evaluated in phase I clinical trials in patients with multiple myeloma and advanced solid tumors. To assess the potential benefit of p97 inhibition as a novel approach for AML therapy, we investigated the efficacy, pharmacodynamics (PD), and pharmacokinetics (PK) of CB-5083 in a panel of human AML cell lines with diverse genetic backgrounds, primary AML specimens from both newly diagnosed and relapsed/refractory patients, and xenograft mouse models of AML. In vitro treatment with CB-5083 potently diminished the viability of AML cell lines (n = 7) and primary CD34+ blasts obtained from patients (n = 10) with IC50s significantly below 1 µM (range 200 - 700 nM) in all lines and specimens evaluated to date. Diminished viability was associated with reduced clonogenic survival and increased apoptosis in AML cell lines and primary blasts. In contrast to many conventional and experimental drugs that are less active against primary AML cells than established AML cell lines, primary cells exhibited sensitivity to CB-5083 that was similar to cell lines. Additionally, CB-5083 was highly active in 3 different cell line models of cytarabine resistance and primary cells from refractory AML patients. This suggests that CB-5083 may be effective for patients who are relapsed/refractory to conventional therapy. In vitro PD analyses demonstrated that CB-5083 rapidly triggered the accumulation of ubiquitin-conjugated proteins, activated the unfolded protein response (UPR), disrupted STAT5 signaling, reduced levels of key STAT5 targets including BCL-xL and PIM-2, and induced apoptosis. The pro-apoptotic effects of CB-5083 were associated with activation of the endoplasmic reticulum (ER) resident initiator caspase-4 and induction of the BH3-only protein NOXA, which has been previously demonstrated to be an important mediator of cell death induced by other agents that disrupt protein homeostasis. RNA sequencing (RNASeq) gene ontology (GO) analyses of MV4-11 and MOLM-13 AML cells following treatment with CB-5083 demonstrated that short-term treatment (6h) caused significant increases in multiple regulators of the unfolded protein response, protein biosynthesis, and other ubiquitin-related pathways (p<0.001). Results were confirmed by qRT-PCR. The in vivo anti-leukemic activity of CB-5083 was investigated in two different xenograft mouse models of AML: the FLT3-ITD+ MV4-11 cell line and APML HL-60 cells. Oral administration of CB-5083 (once daily, 4 days on, 3 days off) was well tolerated and induced disease regression in both xenograft models (p<0.01). In vivo PD studies demonstrated that administration of CB-5083 led to reduced AML cell proliferation (PCNA), to the induction of apoptosis (active caspase-3), and pathway inhibition as evidenced by poly-ubiquitin accumulation and elevated expression of CHOP, GRP78, and NOXA. PK-PD analyses demonstrated a correlation between the kinetics of the in vivo PD effects and drug exposure. Our collective preclinical data demonstrate that p97 inhibition is a very effective novel anti-leukemic strategy and support clinical investigation of CB-5083 in patients with relapsed/refractory AML. Disclosures LE Moigne: Cleave Biosciences: Employment. Rolfe:Cleave Biosciences: Employment. Djakovic:Cleave Biosciences: Employment. Anderson:Cleave Biosciences: Employment. Wustrow:Cleave Biosciences: Employment. Zhou:Cleave Biosciences: Employment. Wong:Cleave Biosciences: Employment. Sekeres:TetraLogic: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Carew:Boehringer Ingelheim: Research Funding.

scholarly journals Unfolded Protein Response and Crohn’s Diseases: A Molecular Mechanism of Wound Healing in the Gut

2021 ◽  
Author(s):  
Chao Li
Keyword(s):  
Er Stress ◽  
Unfolded Protein Response ◽  
Immune Cell ◽  
Macrophage Polarization ◽  
Intestinal Epithelial ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

Endoplasmic reticulum (ER) stress triggers a series of signaling and transcriptional events termed the unfolded protein response (UPR). Severe ER stress is associated with the development of fibrosis in different organs including lung, liver, kidney, heart, and intestine. ER stress is an essential response of epithelial and immune cells in the pathogenesis of inflammatory bowel disease (IBD) including Crohn&rsquo;s disease. Intestinal epithelial cells are susceptible to ER stress-mediated damage due to secretion of a large amount of proteins that are involved in mucosal defense. In other cells, ER stress is linked to myofibroblast activation, extracellular matrix production, macrophage polarization, and immune cell differentiation. This review focuses on the role of UPR in the pathogenesis in IBD from an immunologic perspective. The roles of macrophage and mesenchymal cells in the UPR from in vitro and in vivo animal models are discussed. The links between ER stress and other signaling pathways such as senescence and autophagy are introduced. Recent advances in the understanding of the epigenetic regulation of UPR signaling are also updated here. The future directions of development of the UPR research and therapeutic strategies to manipulate ER stress levels are also reviewed.

scholarly journals Activation of the IRE1α Arm, but not the PERK Arm, of the Unfolded Protein Response Contributes to Fumonisin B1-Induced Hepatotoxicity

Toxins ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 55 ◽  
Author(s):  
Xiaoyi Liu ◽  
Enxiang Zhang ◽  
Shutao Yin ◽  
Chong Zhao ◽  
Lihong Fan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Liver Toxicity ◽  
Fumonisin B1 ◽  
Critical Event ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

Previous studies by us or others have shown that endoplasmic reticulum (ER) stress was activated by fumonisin 1 (FB1) exposure, which is considered to be a critical event in the FB1-induced toxic effect. However, the detailed mechanisms underlying FB1-induced ER stress-mediated liver toxicity remain elusive. The objectives of the present study were designed to address the following issues: (1) the contribution of each arm of the unfolded protein response (UPR); (2) the downstream targets of ER stress that mediated FB1-induced liver toxicity; and (3) the relationship between ER stress and oxidative stress triggered by FB1. We also investigated whether the inhibition of ER stress by its inhibitor could offer protection against FB1-induced hepatotoxicity in vivo, which has not been critically addressed previously. The results showed that the activation of the IRE1α axis, but not of the PERK axis, of UPR contributed to FB1-induced ER stress-mediated hepatocyte toxicity; the activation of the Bax/Bak-mediated mitochondrial pathway lay downstream of IRE1α to trigger mitochondrial-dependent apoptosis in response to FB1; FB1-induced oxidative stress and ER stress augmented each other through a positive feedback mechanism; tauroursodeoxycholic acid (TUDCA)-mediated ER stress inactivation is an effective approach to counteract FB1-induced hepatotoxicity in vivo. The data of the present study allow us to better understand the mechanisms of FB1-induced hepatotoxicity.

scholarly journals Activation of the Unfolded Protein Response Is Required for Defenses against Bacterial Pore-Forming Toxin In Vivo

2008 ◽  
Vol 4 (10) ◽  
pp. e1000176 ◽  
Author(s):  
Larry J. Bischof ◽  
Cheng-Yuan Kao ◽  
Ferdinand C. O. Los ◽  
Manuel R. Gonzalez ◽  
Zhouxin Shen ◽  
...  
Keyword(s):  
Unfolded Protein Response ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response
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