scholarly journals Delayed activation of caspase-independent apoptosis during heart failure in transgenic mice overexpressing caspase inhibitor CrmA

2010 ◽  
Vol 299 (5) ◽  
pp. H1374-H1381 ◽  
Author(s):  
Soochan Bae ◽  
Parco M. Siu ◽  
Sangita Choudhury ◽  
Qingen Ke ◽  
Jun H. Choi ◽  
...  
Keyword(s):  
Heart Failure ◽  
Caspase Inhibitor ◽  
Wild Type ◽  
Caspase Activation ◽  
Response Modifier ◽  
Specific Expression ◽  
Caspase Inhibition ◽  
Cardiac Apoptosis ◽  
Apoptotic Pathways ◽  
Apoptosis Inducing Factor

Although caspase activation is generally thought to be necessary to induce apoptosis, recent evidence suggests that apoptosis can be activated in the setting of caspase inhibition. In this study, we tested the hypothesis that caspase-independent apoptotic pathways contribute to the development of heart failure in the absence of caspase activation. Acute cardiomyopathy was induced using a single dose of doxorubicin (Dox, 20 mg/kg) injected into male wild-type (WT) and transgenic (Tg) mice with a cardiac-specific expression of cytokine response modifier A (CrmA), a known caspase inhibitor. Early (6 day) survival was significantly better in CrmA Tg (81%) than WT (38%) mice. Twelve days after Dox injection, however, the mortality benefit had dissipated, and increased cardiac apoptosis was observed in both groups. There was, however, a significantly greater release of apoptosis-inducing factor (AIF) from mitochondria to cytosol in CrmA Tg compared with WT mice, which suggests that an enhancement of activation in caspase-independent apoptotic pathways had occurred. The administration of a poly(ADP-ribose) polymerase-1 inhibitor, 4-amino-1,8-naphthalimide (4-AN), to Dox-treated mice resulted in significantly improved cardiac function, a significant blockade of AIF released from mitochondria, and decreased cardiac apoptosis. There were also significantly improved survival in WT (18% without 4-AN vs. 89% with 4-AN) and CrmA Tg (13% without 4-AN vs. 93% with 4-AN) mice 12 days after Dox injection. In conclusion, these findings suggest that apoptosis can be induced in the heart lacking caspase activation via caspase-independent pathways and that enabling the inhibition of AIF activation may provide a significant cardiac benefit.

Abstract 1780: Caspase-independent Apoptosis Is Activated In The Late Stage Of Heart Failure In Mice Overexpressing Crma In Vivo

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Soochan Bae ◽  
Parco Siu ◽  
Sangita Choudhury ◽  
Qingen Ke ◽  
Young Y Koh ◽  
...  
Keyword(s):  
Heart Failure ◽  
Similar Rate ◽  
Significant Inhibition ◽  
Parp Inhibition ◽  
Caspase Inhibition ◽  
Cardiac Apoptosis ◽  
Significant Release ◽  
Induced Apoptosis ◽  
Apoptosis Inducing Factor

Caspase inhibition is thought to be an effective strategy for inhibiting apoptosis in heart. Recent data, however, suggest that caspase-independent apoptosis might be activated when caspases are inhibited. Here, we examined whether caspase-independent apoptosis involving apoptosis inducing factor (AIF) is important in the development of heart failure in the setting of caspase inhibition in vivo. Method: We created transgenic mice with cardiac specific overexpression of cytokine response modifier A (CrmA), a known inhibitor of caspases, using αMHC promoter (CrmA Tg mice). A single dose of doxorubicin (DOX; 20 mg/kg) was injected i.p. into male mice to generate acute cardiomyopathy. A quantitative analysis of cardiac apoptosis was performed using TUNEL assay. Results: Caspase activity was completely inhibited in CrmA Tg mice hearts 6 days after DOX injection, whereas the WT hearts showed significant caspase activation. We also observed significantly improved survival in CrmA Tg compared to WT mice (81% vs 38%, p<0.05) 6 days after DOX injection. However, at 12 days, CrmA Tg and WT mice had a similar rate of cardiac apoptosis, and the survival benefit did not persist. Further analysis revealed that CrmA Tg but not WT mice hearts were characterized by a significant release of AIF from the mitochondria at 12 days. This evidence of AIF-induced apoptosis suggests a late activation of AIF in the setting of caspase inhibition. CrmA Tg mice were also pre-treated with 4-AN (4-amino-1,8-napthalimide, 3 mg/kg), a potent inhibitor of PARP, and examined 12 days after DOX injection. PARP is an important regulator of AIF-induced apoptosis, and PARP inhibition significantly improved DOX-impaired cardiac function (+91%, p<0.01) and survival compared to CrmA Tg mice without 4-AN (93% vs. 13%, p<0.05). In addition 4-AN pretreatment resulted in a significant inhibition of PARP activity, blockade of AIF released from mitochondria, and less apoptosis compared to CrmA Tg without 4-AN. Conclusion: In the setting of caspase inhibition, apoptosis can be induced through caspase-independent mechanisms, predominately via AIF, in a model of heart failure in vivo . The concurrent inhibition of AIF activation provides a more effective and complete inhibition of apoptosis.

The Pesticide Metabolites Paraoxon and Malaoxon Induce Cellular Death by Different Mechanisms in Cultured Human Pulmonary Cells

2015 ◽  
Vol 34 (5) ◽  
pp. 433-441 ◽  
Author(s):  
Daniel J. Angelini ◽  
Robert A. Moyer ◽  
Stephanie Cole ◽  
Kristen L. Willis ◽  
Jonathan Oyler ◽  
...  
Keyword(s):  
Cell Death ◽  
Caspase Inhibitor ◽  
Caspase Activation ◽  
Pulmonary Epithelium ◽  
Cellular Death ◽  
Caspase Inhibition ◽  
Pesticide Metabolites ◽  
Pulmonary Cells ◽  
Dose Dependent Increase ◽  
Dose Dependent

Organophosphorus (OP) pesticides are known to induce pulmonary toxicity in both humans and experimental animals. To elucidate the mechanism of OP-induced cytotoxicity, we examined the effects of parathion and malathion and their respective metabolites, paraoxon and malaoxon, on primary cultured human large and small airway cells. Exposure to paraoxon and malaoxon produced a dose-dependent increase in cytotoxicity following a 24-hour exposure, while treatment with parathion or malathion produced no effects at clinically relevant concentrations. Exposure to paraoxon-induced caspase activation, but malaoxon failed to induce this response. Since caspases have a major role in the regulation of apoptosis and cell death, we evaluated OP-induced cell death in the presence of a caspase inhibitor. Pharmacological caspase inhibition protected against paraoxon-induced cell death but not malaoxon-induced cell death. These data suggest that caspase activation is a key signaling element in paraoxon-induced cell death, but not malaoxon-induced cellular death in the pulmonary epithelium.

Role of caspases and NF-κB signaling in hydrogen peroxide- and superoxide-induced hepatocyte apoptosis

2000 ◽  
Vol 278 (5) ◽  
pp. G693-G699 ◽  
Author(s):  
Brett E. Jones ◽  
Chau R. Lo ◽  
Hailing Liu ◽  
Zehra Pradhan ◽  
Lydia Garcia ◽  
...  
Keyword(s):  
Cell Death ◽  
Nuclear Factor Κb ◽  
Caspase Activation ◽  
Hepatocyte Apoptosis ◽  
Oxygen Intermediates ◽  
Caspase Inhibition ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Factor Α ◽  
Hepatocellular Death

Reactive oxygen intermediates (ROI) have been implicated as mediators of hepatocyte death resulting from a variety of forms of liver injury. To delineate the mechanisms that underlie ROI-induced apoptosis, the roles of caspase activation and nuclear factor-κB (NF-κB) signaling were determined in the rat hepatocyte cell line RALA255-10G after treatment with H2O2 or the superoxide generator menadione. By 8 h, H2O2 and menadione caused 26% and 33% cell death, respectively. Death from both ROI occurred by apoptosis as indicated by morphology under fluorescence microscopy, the induction of caspase activation and DNA fragmentation, and the cleavage of poly(ADP-ribose) polymerase. Despite the presence of caspase activation in both forms of apoptosis, caspase inhibition blocked H2O2- but not menadione-induced apoptosis. In contrast, inhibition of NF-κB activation decreased cell death from both ROI. Different ROI, therefore, induce distinct apoptotic pathways in RALA hepatocytes that are both caspase dependent and independent. In contrast to the known protective effect of NF-κB activation in tumor necrosis factor-α-induced hepatocyte apoptosis, NF-κB promotes hepatocellular death from ROI in these cells.

Abstract 14673: Cardiomyocyte Specific Overexpression of Pellino 1 Reverses Sepsis Induced Cardiac Dysfunction in a Murine Model by Reducing Inflammatory Response and Cardiac Cell Death

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Santosh Swaminathan ◽  
Seetur R. Pradeep ◽  
Rickesha I Wilson ◽  
Jacob Campbell ◽  
Mahesh Thirunavukkarasu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Severe Sepsis ◽  
Cardiac Function ◽  
Genetic Model ◽  
Cecal Ligation ◽  
Tnf Alpha ◽  
Wild Type ◽  
Post Surgery ◽  
Novel Approach ◽  
Cardiac Apoptosis

Introduction: Sepsis remains a significant cause of mortality in the intensive care unit till today. Recent research suggests nearly one in four deaths in people with heart failure is caused by sepsis. Overexpression of mammalian Pellino-1 (Peli1), a E3 ubiquitin ligase, causes inhibition of apoptosis, oxidative stress, and preservation of cardiac function in a myocardial infarction model. Therefore, in the present study, we explored the possibility to overcome sepsis mediated heart failure by overexpressing Peli1 (AMPEL1Tg/+) in a mouse model of severe sepsis. Methods: C57BL/6J (WT) and AMPEL1 Tg/+ mice were divided into Wild-type sham (WTS), Wild-type Cecal Ligation and Puncture (WTCLP), AMPEL1 Tg/+ sham (AMPEL1 Tg/+ S) and AMPEL1 Tg/+ CLP. Cardiac function (LVEF, FS) by two-dimensional echocardiography was assessed pre-procedure, at 6, and 24 hours post-surgery. Serum IL-6 and TNF-alpha (ELISA) at 6 hours and cardiac apoptosis (TUNEL assay) at 24 hours were measured. Results are expressed as mean ± SEM. Results: Analysis of echocardiographic parameters (EF, FS) preoperatively and among the sham groups were similar however there was significant preservation of post-procedure LVEF (%) in the AMPEL1 Tg/+ CLP at the 6 hour (AMPEL1 Tg/+ :52.7 ± 3.71 vs WT:40.7 ±2.46, p=0.013, n=10-11) and 24-hour time point (AMPEL1 Tg/+ :63.1 ± 1.63 vs WT:49.3 ± 4.41, p=0.002, n=9-11) compared to WT. Similar trend was observed in estimation of FS (%) at 6 hours (AMPEL1 Tg/+ :26.3 ± 2.22 vs WT:19.3 ±1.37, p=0.014, n=10-11) and 24 hours (AMPEL1 Tg/+ :32.4 ± 1.89 vs WT:24.4 ± 2.67, p=0.031, n=9-11). A marked decrease in serum IL-6 (AMPEL1 Tg/+ :259.7 ± 18.70 vs WT:483.2 ± 24.01, p<0.0001, n=6, pg/mL) and TNF-alpha (AMPEL1 Tg/+ :86.89 ± 14.36 vs WT:161.8 ± 20, p=0.012, n=6, pg/mL) was observed in the AMPEL1 Tg/+ CLP at 6 hours. The preserved cardiac function in CLP was further supported by a noticeable decrease in cardiac apoptosis (% TUNEL positive cells) at 24 hours in the AMPEL1 Tg/+ CLP group (4.7 ± 0.94 vs 11.7 ± 2.82, p=0.040, n=6,) compared to WTCLP. Conclusions: Thus, Peli1 overexpression is a novel approach that preserved cardiac function, reduced inflammatory markers, and apoptosis following severe sepsis in a murine genetic model.

scholarly journals Alopecia in Harlequin mutant mice is associated with reduced AIF protein levels and expression of retroviral elements

2020 ◽  
Author(s):  
Maik Hintze ◽  
Sebastian Griesing ◽  
Marion Michels ◽  
Birgit Blanck ◽  
Lena Wischhof ◽  
...  
Keyword(s):  
Hair Growth ◽  
Transcriptional Regulators ◽  
Mutant Mice ◽  
Wild Type ◽  
Protein Levels ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Keratinocyte Cell ◽  
Apoptosis Inducing Factor ◽  
Hair Cortex

AbstractWe investigated the contribution of apoptosis-inducing factor (AIF), a key regulator of mitochondrial biogenesis, in supporting hair growth. We report that pelage abnormalities developed during hair follicle (HF) morphogenesis in Harlequin (Hq) mutant mice. Fragility of the hair cortex was associated with decreased expression of genes encoding structural hair proteins, though key transcriptional regulators of HF development were expressed at normal levels. Notably, Aifm1 (R200 del) knockin males and Aifm1(R200 del)/Hq females showed minor hair defects, despite substantially reduced AIF levels. Furthermore, we cloned the integrated ecotropic provirus of the Aifm1Hq allele. We found that its overexpression in wild-type keratinocyte cell lines led to down-regulation of HF-specific Krt84 and Krtap3-3 genes without altering Aifm1 or epidermal Krt5 expression. Together, our findings imply that pelage paucity in Hq mutant mice is mechanistically linked to severe AIF deficiency and is associated with the expression of retroviral elements that might potentially influence the transcriptional regulation of structural hair proteins.

Abnormal Spinal Cord Myelination due to Oligodendrocyte Dysfunction in a Model of Huntington’s Disease

2021 ◽  
pp. 1-8
Author(s):  
Costanza Ferrari Bardile ◽  
Harwin Sidik ◽  
Reynard Quek ◽  
Nur Amirah Binte Mohammad Yusof ◽  
Marta Garcia-Miralles ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Oligodendrocyte Progenitor Cells ◽  
Wild Type ◽  
Specific Expression ◽  
Relative Contribution ◽  
Related Proteins ◽  
The Impact ◽  
Cervical Area

Background: The relative contribution of grey matter (GM) and white matter (WM) degeneration to the progressive brain atrophy in Huntington’s disease (HD) has been well studied. The pathology of the spinal cord in HD is comparatively less well documented. Objective: We aim to characterize spinal cord WM abnormalities in a mouse model of HD and evaluate whether selective removal of mutant huntingtin (mHTT) from oligodendroglia rescues these deficits. Methods: Histological assessments were used to determine the area of GM and WM in the spinal cord of 12-month-old BACHD mice, while electron microscopy was used to analyze myelin fibers in the cervical area of the spinal cord. To investigate the impact of inactivation of mHTT in oligodendroglia on these measures, we used the previously described BACHDxNG2Cre mouse line where mHTT is specifically reduced in oligodendrocyte progenitor cells. Results: We show that spinal GM and WM areas are significantly atrophied in HD mice compared to wild-type controls. We further demonstrate that specific reduction of mHTT in oligodendroglial cells rescues the atrophy of spinal cord WM, but not GM, observed in HD mice. Inactivation of mHTT in oligodendroglia had no effect on the density of oligodendroglial cells but enhanced the expression of myelin-related proteins in the spinal cord. Conclusion: Our findings demonstrate that the myelination abnormalities observed in brain WM structures in HD extend to the spinal cord and suggest that specific expression of mHTT in oligodendrocytes contributes to such abnormalities.

scholarly journals Selective Regulation of Apoptosis: the Cytotoxic Lymphocyte Serpin Proteinase Inhibitor 9 Protects against Granzyme B-Mediated Apoptosis without Perturbing the Fas Cell Death Pathway

1998 ◽  
Vol 18 (11) ◽  
pp. 6387-6398 ◽  
Author(s):  
Catherina H. Bird ◽  
Vivien R. Sutton ◽  
Jiuru Sun ◽  
Claire E. Hirst ◽  
Andrea Novak ◽  
...  
Keyword(s):  
Proteinase Inhibitor ◽  
Granzyme B ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Caspase Inhibitor ◽  
Caspase Activation ◽  
Cytotoxic Lymphocyte ◽  
Transfected Cells ◽  
Cell Death Pathway ◽  
Proteinase Inhibitor 9

ABSTRACT Cytotoxic lymphocytes (CLs) induce caspase activation and apoptosis of target cells either through Fas activation or through release of granule cytotoxins, particularly granzyme B. CLs themselves resist granule-mediated apoptosis but are eventually cleared via Fas-mediated apoptosis. Here we show that the CL cytoplasmic serpin proteinase inhibitor 9 (PI-9) can protect transfected cells against apoptosis induced by either purified granzyme B and perforin or intact CLs. A PI-9 P1 mutant (Glu to Asp) is a 100-fold-less-efficient granzyme B inhibitor that no longer protects against granzyme B-mediated apoptosis. PI-9 is highly specific for granzyme B because it does not inhibit eight of the nine caspases tested or protect transfected cells against Fas-mediated apoptosis. In contrast, the P1(Asp) mutant is an effective caspase inhibitor that protects against Fas-mediated apoptosis. We propose that PI-9 shields CLs specifically against misdirected granzyme B to prevent autolysis or fratricide, but it does not interfere with homeostatic deletion via Fas-mediated apoptosis.

scholarly journals Tissue-specific expression of B7x protects from CD4 T cell–mediated autoimmunity

2011 ◽  
Vol 208 (8) ◽  
pp. 1683-1694 ◽  
Author(s):  
Joyce Wei ◽  
P’ng Loke ◽  
Xingxing Zang ◽  
James P. Allison
Keyword(s):  
T Cells ◽  
Pancreatic Islets ◽  
Peripheral Tolerance ◽  
Wild Type ◽  
Autoimmune Encephalomyelitis ◽  
Specific Expression ◽  
Tissue Specific ◽  
Disease Induction ◽  
Deficient Mice ◽  
Experimental Autoimmune

B7x, an inhibitory member of the B7/CD28 superfamily, is highly expressed in a broad range of nonhematopoietic organs, suggesting a role in maintaining peripheral tolerance. As endogenous B7x protein is expressed in pancreatic islets, we investigated whether the molecule inhibits diabetogenic responses. Transfer of disease-inducing BDC2.5 T cells into B7x-deficient mice resulted in a more aggressive form of diabetes than in wild-type animals. This exacerbation of disease correlated with higher frequencies of islet-infiltrating Th1 and Th17 cells. Conversely, local B7x overexpression inhibited the development of autoimmunity, as crossing diabetes-susceptible BDC2.5/B6g7 mice to animals overexpressing B7x in pancreatic islets abrogated disease induction. This protection was caused by the inhibition of IFN-γ production by CD4 T cells and not to a skewing or expansion of Th2 or regulatory T cells. The suppressive function of B7x was also supported by observations from another autoimmune model, experimental autoimmune encephalomyelitis, in which B7x-deficient mice developed exacerbated disease in comparison with wild-type animals. Analysis of central nervous system–infiltrating immune cells revealed that the loss of endogenous B7x resulted in expanded Th1 and Th17 responses. Data from these two autoimmune models provide evidence that B7x expression in the periphery acts as an immune checkpoint to prevent tissue-specific autoimmunity.

scholarly journals Dysfunction of the TP53 tumor suppressor gene in lymphoid malignancies

Blood ◽  
2012 ◽  
Vol 119 (16) ◽  
pp. 3668-3683 ◽  
Author(s):  
Zijun Y. Xu-Monette ◽  
L. Jeffrey Medeiros ◽  
Yong Li ◽  
Robert Z. Orlowski ◽  
Michael Andreeff ◽  
...  
Keyword(s):  
Tp53 Gene ◽  
Suppressor Gene ◽  
Wild Type ◽  
Lymphoid Malignancies ◽  
The Status ◽  
Tp53 Tumor Suppressor Gene ◽  
P53 Activation ◽  
Apoptotic Pathways ◽  
P53 Inactivation ◽  
Tp53 Pathway

AbstractMutations of the TP53 gene and dysregulation of the TP53 pathway are important in the pathogenesis of many human cancers, including lymphomas. Tumor suppression by p53 occurs via both transcription-dependent activities in the nucleus by which p53 regulates transcription of genes involved in cell cycle, DNA repair, apoptosis, signaling, transcription, and metabolism; and transcription-independent activities that induces apoptosis and autophagy in the cytoplasm. In lymphoid malignancies, the frequency of TP53 deletions and mutations is lower than in other types of cancer. Nonetheless, the status of TP53 is an independent prognostic factor in most lymphoma types. Dysfunction of TP53 with wild-type coding sequence can result from deregulated gene expression, stability, and activity of p53. To overcome TP53 pathway inactivation, therapeutic delivery of wild-type p53, activation of mutant p53, inhibition of MDM2-mediated degradation of p53, and activation of p53-dependent and -independent apoptotic pathways have been explored experimentally and in clinical trials. We review the mechanisms of TP53 dysfunction, recent advances implicated in lymphomagenesis, and therapeutic approaches to overcoming p53 inactivation.

Expression of SMRTβ promotes ligand-induced activation of mutated and wild-type retinoid receptors

Blood ◽  
2004 ◽  
Vol 104 (13) ◽  
pp. 4226-4235 ◽  
Author(s):  
Sylvie Côté ◽  
Suzan McNamara ◽  
Daria Brambilla ◽  
Andrea Bianchini ◽  
Giovanni Rizzo ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Nuclear Receptors ◽  
Transcriptional Activation ◽  
Leukemic Cell ◽  
Wild Type ◽  
Specific Expression ◽  
Retinoid Receptors ◽  
Leukemic Cell Lines ◽  
All Trans Retinoic Acid ◽  
New Evidence

Abstract Nuclear receptors are ligand-modulated transcription factors regulated by interactions with corepressors and coactivators, whose functions are not fully understood. Acute promyelocytic leukemia (APL) is characterized by a translocation, t(15;17), that produces a PML/RARα fusion oncoprotein, whose abnormal transcriptional function is successfully targeted by pharmacologic levels of all-trans-retinoic acid (ATRA). Mutations in the ligand-binding domain of PML/RARα that confer resistance to ATRA have been studied by expression in nonhematopoietic cells, such as Cos-1. Here, we show that ATRA binding and transcriptional activation by the same PML/RARα mutant differ markedly between nonhematopoietic and leukemic cell lines. Differential expression of the corepressor isoform silencing mediator for retinoid and thyroid receptors β (SMRTβ) correlates with increased ligand binding and transcription by the mutant PML/RARα. Transient and stable overexpression of SMRTβ in hematopoietic cells that only express SMRTα increased ATRA binding, ligand-induced transcription, and ATRA-induced cell differentiation. This effect may not be limited to abnormal nuclear receptors, because overexpression of SMRTβ increased ATRA-induced binding and transcriptional activation of wild-type receptors PML/RARα and RARα. Our results suggest a novel role for the SMRTβ isoform whereby its cell-specific expression may influence the binding and transcriptional capacities of nuclear receptors, thus providing new evidence of distinct functions of corepressor isoforms and adding complexity to transcriptional regulation.

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