scholarly journals Lack of ZnT8 protects pancreatic islets from hypoxia- and cytokine induced cell death

2022 ◽  
Author(s):  
Maria Karsai ◽  
Richard A Zuellig ◽  
Roger Lehmann ◽  
Federica Cuozzo ◽  
Daniela Nasteska ◽  
...  
Keyword(s):  
Cell Death ◽  
Islet Cell ◽  
Islet Cells ◽  
Zinc Content ◽  
Zinc Homeostasis ◽  
Wild Type ◽  
Zinc Chelator ◽  
Zinc Concentrations ◽  
Processing And Storage

Pancreatic β-cells depend on the well-balanced regulation of cytosolic zinc concentrations, providing sufficient zinc ions for the processing and storage of insulin, but avoiding toxic effects. The zinc transporter ZnT8, encoded by SLC30A8, is a key player regarding islet cell zinc homeostasis, and polymorphisms in this gene are associated with altered type 2 diabetes susceptibility in man. The objective of this study was to investigate the role of ZnT8 and zinc in situations of cellular stress as hypoxia or inflammation. Isolated islets of wild-type and global ZnT8-/- mice were exposed to hypoxia or cytokines and cell death was measured. To explore the role of changing intracellular Zn2+ concentrations, wild-type islets were exposed to different zinc concentrations using zinc chloride or the zinc chelator N,N,N′,N′-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN). Hypoxia or cytokine (TNFα, IFNγ, IL1β) treatment induced islet cell death, but to a lesser extent in islets from ZnT8-/- mice, which were shown to have a reduced zinc content. Similarly, chelation of zinc with TPEN reduced cell death in wild-type islets treated with hypoxia or cytokines, whereas increased zinc concentrations aggravated the effects of these stressors. This study demonstrates a reduced rate of cell death in islets from ZnT8-/- mice as compared to wild-type islets when exposed to two distinct cellular stressors, hypoxia or cytotoxic cytokines. This protection from cell death is, in part, mediated by a reduced zinc content in islet cells of ZnT8-/- mice. These findings may be relevant for altered diabetes burden in carriers of risk SLC30A8 alleles in man.

scholarly journals Salicylic Acid Accumulation Controlled by LSD1 Is Essential in Triggering Cell Death in Response to Abiotic Stress

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 962
Author(s):  
Maciej Jerzy Bernacki ◽  
Anna Rusaczonek ◽  
Weronika Czarnocka ◽  
Stanisław Karpiński
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Abiotic Stress ◽  
Wild Type ◽  
Pr Genes ◽  
Genes Expression ◽  
Salicylic Acid Accumulation ◽  
Cell Death Phenotype ◽  
Insight Into

Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells. LESION SIMULATING DISEASE 1 (LSD1) is one of the best-known cell death regulators in Arabidopsis thaliana. The lsd1 mutant, lacking functional LSD1 protein, accumulates SA and is conditionally susceptible to many biotic and abiotic stresses. In order to get more insight into the role of LSD1-dependent regulation of SA accumulation during cell death, we crossed the lsd1 with the sid2 mutant, caring mutation in ISOCHORISMATE SYNTHASE 1(ICS1) gene and having deregulated SA synthesis, and with plants expressing the bacterial nahG gene and thus decomposing SA to catechol. In response to UV A+B irradiation, the lsd1 mutant exhibited clear cell death phenotype, which was reversed in lsd1/sid2 and lsd1/NahG plants. The expression of PR-genes and the H2O2 content in UV-treated lsd1 were significantly higher when compared with the wild type. In contrast, lsd1/sid2 and lsd1/NahG plants demonstrated comparability with the wild-type level of PR-genes expression and H2O2. Our results demonstrate that SA accumulation is crucial for triggering cell death in lsd1, while the reduction of excessive SA accumulation may lead to a greater tolerance toward abiotic stress.

scholarly journals Bub1 mediates cell death in response to chromosome missegregation and acts to suppress spontaneous tumorigenesis

2007 ◽  
Vol 179 (2) ◽  
pp. 255-267 ◽  
Author(s):  
Karthik Jeganathan ◽  
Liviu Malureanu ◽  
Darren J. Baker ◽  
Susan C. Abraham ◽  
Jan M. van Deursen
Keyword(s):  
Cell Death ◽  
Chromosome Segregation ◽  
Physiological Role ◽  
Mitotic Checkpoint ◽  
Critical Threshold ◽  
Wild Type ◽  
Checkpoint Protein ◽  
Chromosome Missegregation ◽  
Mitotic Checkpoint Protein

The physiological role of the mitotic checkpoint protein Bub1 is unknown. To study this role, we generated a series of mutant mice with a gradient of reduced Bub1 expression using wild-type, hypomorphic, and knockout alleles. Bub1 hypomorphic mice are viable, fertile, and overtly normal despite weakened mitotic checkpoint activity and high percentages of aneuploid cells. Bub1 haploinsufficient mice, which have a milder reduction in Bub1 protein than Bub1 hypomorphic mice, also exhibit reduced checkpoint activity and increased aneuploidy, but to a lesser extent. Although cells from Bub1 hypomorphic and haploinsufficient mice have similar rates of chromosome missegregation, cell death after an aberrant separation decreases dramatically with declining Bub1 levels. Importantly, Bub1 hypomorphic mice are highly susceptible to spontaneous tumors, whereas Bub1 haploinsufficient mice are not. These findings demonstrate that loss of Bub1 below a critical threshold drives spontaneous tumorigenesis and suggest that in addition to ensuring proper chromosome segregation, Bub1 is important for mediating cell death when chromosomes missegregate.

A group of genes required for maintenance of the amnioserosa tissue in Drosophila

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1343-1352 ◽  
Author(s):  
L.H. Frank ◽  
C. Rushlow
Keyword(s):  
Cell Death ◽  
Cell Loss ◽  
Dorsal Side ◽  
Drosophila Embryo ◽  
Epithelial Tissue ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Germ Band ◽  
Initial Development

The amnioserosa is an extraembryonic, epithelial tissue that covers the dorsal side of the Drosophila embryo. The initial development of the amnioserosa is controlled by the dorsoventral patterning genes. Here we show that a group of genes, which we refer to as the U-shaped-group (ush-group), is required for maintenance of the amnioserosa tissue once it has differentiated. Using several molecular markers, we examined amnioserosa development in the ush-group mutants: u-shaped (ush), hindsight (hnt), serpent (srp) and tail-up (tup). Our results show that the amnioserosa in these mutants is specified correctly and begins to differentiate as in wild type. However, following germ-band extension, there is a premature loss of the amnioserosa. We demonstrate that this cell loss is a consequence of programmed cell death (apoptosis) in ush, hnt and srp, but not in tup. We discuss the role of the ush-group genes in maintaining the amnioserosa's viability. We also discuss a possible role for the amnioserosa in germ-band retraction in light of these mutants' unretracted phenotype.

Role of the Interventional Radiologist in Pancreatic Whole Organ and Islet Cell Transplantation

2019 ◽  
Vol 03 (04) ◽  
pp. 314-325
Author(s):  
Ketan Y. Shah ◽  
Russell O. Simpson ◽  
Yifan Wang ◽  
Obi T. Okoye ◽  
Mithil B. Pandhi ◽  
...  
Keyword(s):  
Cell Transplantation ◽  
Islet Cell ◽  
Islet Cells ◽  
Portal System ◽  
Cell Transplant ◽  
Pancreatic Islet Cells ◽  
Islet Cell Transplantation ◽  
Image Guided ◽  
Treatment Of Diabetes

AbstractPancreas transplantation is an exciting therapy which has been used for several decades in the treatment of diabetes mellitus. It can be performed as either a whole organ or islet cell transplant. The role of interventional radiologists in the management of whole organ transplants is evolving and includes treatment of postoperative complications and graft biopsy to evaluate for rejection. An in-depth understanding of the transplant anatomy and variations is a fundamental tool in performing these interventions successfully. Islet cell transplantation entails delivery of purified donor pancreatic islet cells into the recipient portal vein. Because of their expertise in image-guided access to the portal system, interventional radiologists play a crucial role in this procedure. The purpose of this article is to review the indications, anatomy, complications, and outcomes of both whole organ and islet cell pancreas transplants, followed by a discussion of the role of interventional radiologists in each procedure.

Abstract 174: The BH3-Only Protein BNIP3 Induces Mitochondrial Clearance via Multiple Pathways

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Eileen R Gonzalez ◽  
Babette Hammerling ◽  
Rita Hanna ◽  
Dieter A Kubli ◽  
Åsa B Gustafsson
Keyword(s):  
Cell Death ◽  
Ubiquitin Ligase ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
Wild Type ◽  
Potent Inducer ◽  
Autophagy Pathway ◽  
Endosomal Pathway ◽  
In Cells

Autophagy plays an important role in cellular quality control and is responsible for removing protein aggregates and dysfunctional organelles. BNIP3 is an atypical BH3-only protein which is known to cause mitochondrial dysfunction and cell death in the myocardium. Interestingly, BNIP3 can also protect against cell death by promoting removal of dysfunctional mitochondria via autophagy (mitophagy). We have previously reported that BNIP3 is a potent inducer of mitophagy in cardiac myocytes and that BNIP3 contains an LC3 Interacting Region (LIR) that binds to LC3 on the autophagosome, tethering the mitochondrion to the autophagosome for engulfment. However, the molecular mechanism(s) underlying BNIP3-mediated mitophagy are still unclear. In this study, we discovered that BNIP3 can mediate mitochondrial clearance in cells even in the absence of a functional autophagy pathway. We found that overexpression of BNIP3 led to significant clearance of mitochondria in both wild type (WT) and autophagy deficient Atg5-/- MEFs. BNIP3 caused an increase in LC3II levels in WT MEFs, indicating increased formation of autophagosomes. In contrast, LC3II was undetectable in Atg5-/- MEFs. Furthermore, we found that BNIP3-mediated clearance in WT and Atg5-/- MEFs did not require the presence of Parkin, an E3 ubiquitin ligase which plays a critical role in clearing dysfunctional mitochondria in cells. Also, overexpression of Parkin did not enhance BNIP3-mediated mitochondrial clearance. When investigating activation of alternative cellular degradation pathways, we found that BNIP3 induced activation of the endosomal-lysosomal pathway in both WT and Atg5-/- MEFs. Mutating the LC3 binding site in BNIP3 did not interfere with the activation of the endosomal pathway and clearance of mitochondria in Atg5-/- MEFs. Thus, these findings suggest that BNIP3 can promote clearance of mitochondria via multiple pathways in cells. The role of autophagy in removing mitochondria is already well established and we are currently exploring the roles of the endosomal and alternative autophagy pathways in BNIP3-mediated mitochondrial clearance in myocytes.

Characterization of siRNA-Mediated SBDS-Knockdown Cells: Specific Hypersensitivity to Fas Stimulation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 386-386 ◽  
Author(s):  
Ken-ichiro Watanabe ◽  
Yigal Dror
Keyword(s):  
Cell Death ◽  
Content Analysis ◽  
Rna Polymerase ◽  
Hela Cells ◽  
Dna Content ◽  
Wild Type ◽  
Cell Death Pathway ◽  
Hela Cell Lines ◽  
And Control

Abstract Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by bone marrow failure, pancreatic insufficiency, and a marked propensity for myelodysplastic syndrome and leukemia. Approximately 90% of the patients have mutations in the SBDS gene. Recent studies suggested a role of the yeast SBDS homologue, YLR022C, in RNA processing and ribosomal biogenesis. However, the function of the human SBDS has not been clarified yet. We previously showed that marrow cells from SDS patients are characterized by accelerated apoptosis, overexpression of Fas and hypersensitivity to Fas stimulation. To study the function of SBDS and determine whether the above abnormalities are caused by deficiency of SBDS, we established stably transfected Hela cell lines expressing two different siRNAs against SBDS and lines expressing scrambled siRNA control. SBDS-knockdown was confirmed by Western blotting using polyclonal chicken anti-human SBDS antibody. The SBDS expression in the scrambled siRNA control cells was comparable to that of wild-type Hela cells. DNA content analysis by propidium iodide staining showed a prominent increase in sub-G1 population in asynchronous, non-treated SBDS-knockdown cells, suggesting that these cells are prone to cell death, however, no cell cycle arrest was noted. To further characterize the SBDS-knockdown cells, we examined their sensitivity to four groups of cell death inducers: DNA damaging agents (etoposide, cisplatin, and doxorubicin), transcriptional inhibitors (actinomycin D and α-amanitin), translation blocker (cycloheximide), and Fas pathway activator (agonistic anti-Fas antibody CH-11). Dose-response curves were obtained by MTT assay performed 48 hrs after treatment of the cells with the reagents. Interestingly, SBDS-deleted cells showed marked hypersensitivity to CH-11; while 3 μ g/ml of CH-11 reduced the survival fraction to 50% in wild-type and control cells, a similar effect was obtained at 0.02 μ g/ml in the SBDS-deleted cells. The hypersensitivity to Fas stimulation was also demonstrated by DNA content analysis. Based on the possible role of the yeast SBDS orthologue in RNA metabolism, we anticipated that the SBDS-deficient cells would be hypersensitive to the transcription inhibitors. However, even at concentrations which completely abolished RNA polymerase I or RNA polymerase II activity as determined by BrUTP labeling, the sensitivity of the SBDS-knockdown cells to the transciptional inhibitors was not remarkably different from that of the control or wild type cells. Similarly, the sensitivity to the genotoxic agents and protein synthesis blocker was not obviously different between the SBDS-deficient and proficient cells. To study the mechanism for Fas hypersensitivity, we analyzed Fas expression by flow cytometry using Cy5-conjugated anti-CD95 antibody and found overexpression of Fas in the SBDS-deleted cells in comparison with the Fas expression in the wild-type and control cells. Although further investigation is needed, these results suggest that the SBDS protein might be involved in cell death pathway, especially in the regulation of Fas-mediated apoptosis. The siRNA-mediated SBDS knock-down Hela cells duplicate important features of SDS cells, and may serve as a useful model to investigate the function of the human SBDS protein.

scholarly journals Unraveling the role of the ghrelin gene peptides in the endocrine pancreas

2010 ◽  
Vol 45 (3) ◽  
pp. 107-118 ◽  
Author(s):  
Riccarda Granata ◽  
Alessandra Baragli ◽  
Fabio Settanni ◽  
Francesca Scarlatti ◽  
Ezio Ghigo
Keyword(s):  
Pancreatic Islets ◽  
Cell Biology ◽  
Islet Cell ◽  
Endocrine Pancreas ◽  
Islet Cells ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Islet Cell ◽  
Ghrelin Gene

The ghrelin gene peptides include acylated ghrelin (AG), unacylated ghrelin (UAG), and obestatin (Ob). AG, mainly produced by the stomach, exerts its central and peripheral effects through the GH secretagogue receptor type 1a (GHS-R1a). UAG, although devoid of GHS-R1a-binding affinity, is an active peptide, sharing with AG many effects through an unknown receptor. Ob was discovered as the G-protein-coupled receptor 39 (GPR39) ligand; however, its physiological actions remain unclear. The endocrine pancreas is necessary for glucose homeostasis maintenance. AG, UAG, and Ob are expressed in both human and rodent pancreatic islets from fetal to adult life, and the pancreas is the major source of ghrelin in the perinatal period. GHS-R1a and GPR39 expression has been shown in β-cells and islets, as well as specific binding sites for AG, UAG, and Ob. Ghrelin colocalizes with glucagon in α-islet cells, but is also uniquely expressed in ε-islet cells, suggesting a role in islet function and development. Indeed, AG, UAG, and Ob regulate insulin secretion in β-cells and isolated islets, promote β-cell proliferation and survival, inhibit β-cell and human islet cell apoptosis, and modulate the expression of genes that are essential in pancreatic islet cell biology. They even induce β-cell regeneration and prevent diabetes in streptozotocin-treated neonatal rats. The receptor(s) mediating their effects are not fully characterized, and a signaling crosstalk has been suggested. The present review summarizes the newest findings on AG, UAG, and Ob expression in pancreatic islets and the role of these peptides on β-cell development, survival, and function.

scholarly journals Role of Calcium in Pancreatic Islet Cell Death by IFN-γ/TNF-α

2004 ◽  
Vol 172 (11) ◽  
pp. 7008-7014 ◽  
Author(s):  
Inik Chang ◽  
Namjoo Cho ◽  
Sunshin Kim ◽  
Ja Young Kim ◽  
Eunshil Kim ◽  
...  
Keyword(s):  
Cell Death ◽  
Pancreatic Islet ◽  
Islet Cell ◽  
Pancreatic Islet Cell ◽  
Tnf Α ◽  
Ifn Γ

scholarly journals Essential Roles of Receptor-Interacting Protein and TRAF2 in Oxidative Stress-Induced Cell Death

2004 ◽  
Vol 24 (13) ◽  
pp. 5914-5922 ◽  
Author(s):  
Han-Ming Shen ◽  
Yong Lin ◽  
Swati Choksi ◽  
Jamie Tran ◽  
Tian Jin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Tumor Necrosis Factor Receptor ◽  
Membrane Lipid ◽  
Critical Event ◽  
Wild Type ◽  
Embryonic Fibroblasts ◽  
Interacting Protein ◽  
Necrosis Factor

ABSTRACT Oxidative stress and reactive oxygen species (ROS) can elicit and modulate various physiological and pathological processes, including cell death. However, the mechanisms controlling ROS-induced cell death are largely unknown. Data from this study suggest that receptor-interacting protein (RIP) and tumor necrosis factor receptor (TNFR)-associated factor 2 (TRAF2), two key effector molecules of TNF signaling, are essential for ROS-induced cell death. We found that RIP−/− or TRAF2−/− mouse embryonic fibroblasts (MEF) are resistant to ROS-induced cell death when compared to wild-type cells, and reconstitution of RIP and TRAF2 gene expression in their respective deficient MEF cells restored their sensitivity to H2O2-induced cell death. We also found that RIP and TRAF2 form a complex upon H2O2 exposure, but without the participation of TNFR1. The colocalization of RIP with a membrane lipid raft marker revealed a possible role of lipid rafts in the transduction of cell death signal initiated by H2O2. Finally, our results demonstrate that activation of c-Jun NH2-terminal kinase 1 is a critical event downstream of RIP and TRAF2 in mediating ROS-induced cell death. Therefore, our study uncovers a novel signaling pathway regulating oxidative stress-induced cell death.

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