scholarly journals Defective ATG16L1-mediated removal of IRE1α drives Crohn’s disease–like ileitis

2017 ◽  
Vol 214 (2) ◽  
pp. 401-422 ◽  
Author(s):  
Markus Tschurtschenthaler ◽  
Timon E. Adolph ◽  
Jonathan W. Ashcroft ◽  
Lukas Niederreiter ◽  
Richa Bharti ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Er Stress ◽  
Paneth Cell ◽  
Protective Role ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Unfolded Protein ◽  
Antimicrobial Function ◽  
The Unfolded Protein Response

ATG16L1T300A, a major risk polymorphism in Crohn’s disease (CD), causes impaired autophagy, but it has remained unclear how this predisposes to CD. In this study, we report that mice with Atg16l1 deletion in intestinal epithelial cells (IECs) spontaneously develop transmural ileitis phenocopying ileal CD in an age-dependent manner, driven by the endoplasmic reticulum (ER) stress sensor IRE1α. IRE1α accumulates in Paneth cells of Atg16l1ΔIEC mice, and humans homozygous for ATG16L1T300A exhibit a corresponding increase of IRE1α in intestinal epithelial crypts. In contrast to a protective role of the IRE1β isoform, hyperactivated IRE1α also drives a similar ileitis developing earlier in life in Atg16l1;Xbp1ΔIEC mice, in which ER stress is induced by deletion of the unfolded protein response transcription factor XBP1. The selective autophagy receptor optineurin interacts with IRE1α, and optineurin deficiency amplifies IRE1α levels during ER stress. Furthermore, although dysbiosis of the ileal microbiota is present in Atg16l1;Xbp1ΔIEC mice as predicted from impaired Paneth cell antimicrobial function, such structural alteration of the microbiota does not trigger ileitis but, rather, aggravates dextran sodium sulfate–induced colitis. Hence, we conclude that defective autophagy in IECs may predispose to CD ileitis via impaired clearance of IRE1α aggregates during ER stress at this site.

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’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 Single-cell analysis of colonic epithelium reveals unexpected shifts in cellular composition and molecular phenotype in treatment-naïve adult Crohn’s disease

2021 ◽  
Author(s):  
Matt Kanke ◽  
Meaghan M. Kennedy ◽  
Sean Connelly ◽  
Matthew Schaner ◽  
Michael T. Shanahan ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Single Cell ◽  
Association Studies ◽  
Paneth Cell ◽  
Genome Wide Association Studies ◽  
Intestinal Epithelial ◽  
Cell Type ◽  
Aberrant Expression ◽  
Treatment Naïve

AbstractThe intestinal epithelial barrier is comprised of a monolayer of specialized intestinal epithelial cells (IECs) that are critical in maintaining gut mucosal homeostasis. Dysfunction within various IEC fractions can increase intestinal permeability, resulting in a chronic and debilitating condition known as Crohn’s disease (CD). Defining the molecular changes in each IEC type in CD will contribute to an improved understanding of the pathogenic processes and the identification of potential therapeutic targets. Here we performed, for the first time at single-cell resolution, a direct comparison of the colonic epithelial cellular and molecular landscape between treatment-naïve adult CD and non-IBD control patients. Our analysis revealed that in CD patients there is a significant skew in the colonic epithelial cellular distribution away from canonical LGR5+ stem cells, located at the crypt-bottom, and toward one specific subtype of mature colonocytes, located at the crypt-top. Further analysis revealed unique changes to gene expression programs in every major cell type, including a previously undescribed suppression in CD of most enteroendocrine driver genes as well as L-cell markers including GCG. We also dissect a previously poorly understood SPIB+ cell cluster, revealing at least four sub-clusters that exhibit unique features. One of these SPIB+ sub-clusters expresses crypt-top colonocyte markers and is significantly up-regulated in CD, whereas another sub-cluster strongly expresses and stains positive for lysozyme (albeit no other canonical Paneth cell marker), which surprisingly is greatly reduced in expression in CD. Finally, through integration with data from genome-wide association studies, we show that genes implicated in CD risk exhibit heretofore unknown cell-type specific patterns of aberrant expression in CD, providing unprecedented insight into the potential biological functions of these genes.

scholarly journals Endoplasmic reticulum chaperone BiP/GRP78 knockdown leads to autophagy and cell death of arginine vasopressin neurons in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yohei Kawaguchi ◽  
Daisuke Hagiwara ◽  
Takashi Miyata ◽  
Yuichi Hodai ◽  
Junki Kurimoto ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Arginine Vasopressin ◽  
Urine Volume ◽  
Neuronal Loss ◽  
Protective Role ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Vasopressin Neurons

AbstractThe immunoglobulin heavy chain binding protein (BiP), also referred to as 78-kDa glucose-regulated protein (GRP78), is a pivotal endoplasmic reticulum (ER) chaperone which modulates the unfolded protein response under ER stress. Our previous studies showed that BiP is expressed in arginine vasopressin (AVP) neurons under non-stress conditions and that BiP expression is upregulated in proportion to the increased AVP expression under dehydration. To clarify the role of BiP in AVP neurons, we used a viral approach in combination with shRNA interference for BiP knockdown in mouse AVP neurons. Injection of a recombinant adeno-associated virus equipped with a mouse AVP promoter and BiP shRNA cassette provided specific BiP knockdown in AVP neurons of the supraoptic (SON) and paraventricular nuclei (PVN) in mice. AVP neuron-specific BiP knockdown led to ER stress and AVP neuronal loss in the SON and PVN, resulting in increased urine volume due to lack of AVP secretion. Immunoelectron microscopy of AVP neurons revealed that autophagy was activated through the process of AVP neuronal loss, whereas no obvious features characteristic of apoptosis were observed. Pharmacological inhibition of autophagy by chloroquine exacerbated the AVP neuronal loss due to BiP knockdown, indicating a protective role of autophagy in AVP neurons under ER stress. In summary, our results demonstrate that BiP is essential for the AVP neuron system.

scholarly journals Paneth cell α-defensin misfolding correlates with dysbiosis and ileitis in Crohn’s disease model mice

2020 ◽  
Vol 3 (6) ◽  
pp. e201900592
Author(s):  
Yu Shimizu ◽  
Kiminori Nakamura ◽  
Aki Yoshii ◽  
Yuki Yokoi ◽  
Mani Kikuchi ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Er Stress ◽  
Disease Progression ◽  
Intestinal Microbiota ◽  
Disulfide Bonds ◽  
Paneth Cell ◽  
Paneth Cells ◽  
Intestinal Lumen ◽  
Reduced Form

Crohn’s disease (CD) is an intractable inflammatory bowel disease, and dysbiosis, disruption of the intestinal microbiota, is associated with CD pathophysiology. ER stress, disruption of ER homeostasis in Paneth cells of the small intestine, and α-defensin misfolding have been reported in CD patients. Because α-defensins regulate the composition of the intestinal microbiota, their misfolding may cause dysbiosis. However, whether ER stress, α-defensin misfolding, and dysbiosis contribute to the pathophysiology of CD remains unknown. Here, we show that abnormal Paneth cells with markers of ER stress appear in SAMP1/YitFc, a mouse model of CD, along with disease progression. Those mice secrete reduced-form α-defensins that lack disulfide bonds into the intestinal lumen, a condition not found in normal mice, and reduced-form α-defensins correlate with dysbiosis during disease progression. Moreover, administration of reduced-form α-defensins to wild-type mice induces the dysbiosis. These data provide novel insights into CD pathogenesis induced by dysbiosis resulting from Paneth cell α-defensin misfolding and they suggest further that Paneth cells may be potential therapeutic targets.

Genomic ATG16L1 risk allele-restricted Paneth cell ER stress in quiescent Crohn's disease

Gut ◽  
2013 ◽  
Vol 63 (7) ◽  
pp. 1081-1091 ◽  
Author(s):  
J Jasper Deuring ◽  
Gwenny M Fuhler ◽  
Sergey R Konstantinov ◽  
Maikel P Peppelenbosch ◽  
Ernst J Kuipers ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Er Stress ◽  
Risk Allele ◽  
Paneth Cell

scholarly journals Glucocorticoids alleviate intestinal ER stress by enhancing protein folding and degradation of misfolded proteins

2013 ◽  
Vol 210 (6) ◽  
pp. 1201-1216 ◽  
Author(s):  
Indrajit Das ◽  
Chin Wen Png ◽  
Iulia Oancea ◽  
Sumaira Z. Hasnain ◽  
Rohan Lourie ◽  
...  
Keyword(s):  
Protein Folding ◽  
Glucocorticoid Receptor ◽  
Er Stress ◽  
Misfolded Proteins ◽  
Secretory Cells ◽  
Dependent Manner ◽  
Unfolded Protein ◽  
Genes Encoding ◽  
Glycosylation Inhibitor ◽  
The Unfolded Protein Response

Endoplasmic reticulum (ER) stress in intestinal secretory cells has been linked with colitis in mice and inflammatory bowel disease (IBD). Endogenous intestinal glucocorticoids are important for homeostasis and glucocorticoid drugs are efficacious in IBD. In Winnie mice with intestinal ER stress caused by misfolding of the Muc2 mucin, the glucocorticoid dexamethasone (DEX) suppressed ER stress and activation of the unfolded protein response (UPR), substantially restoring goblet cell Muc2 production. In mice lacking inflammation, a glucocorticoid receptor antagonist increased ER stress, and DEX suppressed ER stress induced by the N-glycosylation inhibitor, tunicamycin (Tm). In cultured human intestinal secretory cells, in a glucocorticoid receptor-dependent manner, DEX suppressed ER stress and UPR activation induced by blocking N-glycosylation, reducing ER Ca2+ or depleting glucose. DEX up-regulated genes encoding chaperones and elements of ER-associated degradation (ERAD), including EDEM1. Silencing EDEM1 partially inhibited DEX’s suppression of misfolding-induced ER stress, showing that DEX enhances ERAD. DEX inhibited Tm-induced MUC2 precursor accumulation, promoted production of mature mucin, and restored ER exit and secretion of Winnie mutant recombinant Muc2 domains, consistent with enhanced protein folding. In IBD, glucocorticoids are likely to ameliorate ER stress by promoting correct folding of secreted proteins and enhancing removal of misfolded proteins from the ER.

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

2021 ◽  
Vol 3 (1) ◽  
pp. 31-43
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’s disease (CD). 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 the 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 the 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 An INF-STAT Axis Augments Tissue Damage and Inflammation in a Mouse Model of Crohn's Disease

2021 ◽  
Vol 8 ◽  
Author(s):  
Iris Stolzer ◽  
Anja Dressel ◽  
Mircea T. Chiriac ◽  
Markus F. Neurath ◽  
Claudia Günther
Keyword(s):  
Cell Death ◽  
Small Intestine ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Cell Function ◽  
Paneth Cell ◽  
Intestinal Epithelial ◽  
Jak Inhibitors ◽  
Inflammatory Bowel ◽  
Epithelial Cell Death

Blocking interferon-function by therapeutic intervention of the JAK-STAT-axis is a novel promising treatment option for inflammatory bowel disease (IBD). Although JAK inhibitors have proven efficacy in patients with active ulcerative colitis (UC), they failed to induce clinical remission in patients with Crohn's disease (CD). This finding strongly implicates a differential contribution of JAK signaling in both entities. Here, we dissected the contribution of different STAT members downstream of JAK to inflammation and barrier dysfunction in a mouse model of Crohn's disease like ileitis and colitis (Casp8ΔIEC mice). Deletion of STAT1 in Casp8ΔIEC mice was associated with reduced cell death and a partial rescue of Paneth cell function in the small intestine. Likewise, organoids derived from the small intestine of these mice were less sensitive to cell death triggered by IBD-key cytokines such as TNFα or IFNs. Further functional in vitro and in vivo analyses revealed the impairment of MLKL-mediated necrosis as a result of deficient STAT1 function, which was in turn associated with improved cell survival. However, a decrease in inflammatory cell death was still associated with mild inflammation in the small intestine. The impact of STAT1 signaling on gastrointestinal inflammation dependent on the localization of inflammation, as STAT1 is essential for intestinal epithelial cell death regulation in the small intestine, whereas it is not the key factor for intestinal epithelial cell death in the context of colitis. Of note, additional deletion of STAT2 was not sufficient to restore Paneth cell function but strongly ameliorated ileitis. In summary, we provide here compelling molecular evidence that STAT1 and STAT2, both contribute to intestinal homeostasis, but have non-redundant functions. Our results further demonstrate that STATs individually affect the distinct pathophysiology of inflammation in the ileum and colon, respectively, which might explain the diverse outcome of JAK inhibitors on inflammatory bowel diseases.

scholarly journals The unfolded protein response in Pichia pastoris without external stressing stimuli

2020 ◽  
Vol 20 (7) ◽  
Author(s):  
Yasmin Nabilah Binti Mohd Fauzee ◽  
Naoki Taniguchi ◽  
Yuki Ishiwata-Kimata ◽  
Hiroshi Takagi ◽  
Yukio Kimata
Keyword(s):  
Pichia Pastoris ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Gene Knockout ◽  
Transmembrane Protein ◽  
Dependent Manner ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Stress Dependent ◽  
Protein Response

ABSTRACT Dysfunction or capacity shortage of the endoplasmic reticulum (ER) is cumulatively called ER stress and provokes the unfolded protein response (UPR). In various yeast species, the ER-located transmembrane protein Ire1 is activated upon ER stress and performs the splicing reaction of HAC1 mRNA, the mature form of which is translated into a transcription factor protein that is responsible for the transcriptome change on the UPR. Here we carefully assessed the splicing of HAC1 mRNA in Pichia pastoris (Komagataella phaffii) cells. We found that, inconsistent with previous reports by others, the HAC1 mRNA was substantially, but partially, spliced even without ER-stressing stimuli. Unlike Saccharomyces cerevisiae, growth of P. pastoris was significantly retarded by the IRE1-gene knockout mutation. Moreover, P. pastoris cells seemed to push more abundant proteins into the secretory pathway than S. cerevisiae cells. We also suggest that P. pastoris Ire1 has the ability to control its activity stringently in an ER stress-dependent manner. We thus propose that P. pastoris cells are highly ER-stressed possibly because of the high load of endogenous proteins into the ER.

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