scholarly journals Involvement of Bcl-xL in Neuronal Function and Development

2021 ◽  
Vol 22 (6) ◽  
pp. 3202
Author(s):  
Julie Bas ◽  
Trang Nguyen ◽  
Germain Gillet
Keyword(s):  
Cell Death ◽  
Synaptic Transmission ◽  
Neuronal Development ◽  
Morphological Changes ◽  
B Cell Lymphoma ◽  
High Energy ◽  
Mitochondrial Outer Membrane ◽  
Knock Out ◽  
Axon Pruning ◽  
Transient Activation

The B-cell lymphoma (Bcl-2) family of proteins are mainly known for their role in the regulation of apoptosis by preventing pore formation at the mitochondrial outer membrane and subsequent caspase activation. However, Bcl-2 proteins also have non-canonical functions, independent of apoptosis. Indeed, the cell death machinery, including Bcl-2 homologs, was reported to be essential for the central nervous system (CNS), notably with respect to synaptic transmission and axon pruning. Here we focused on Bcl-xL, a close Bcl-2 homolog, which plays a major role in neuronal development, as bclx knock out mice prematurely die at embryonic day 13.5, showing massive apoptosis in the CNS. In addition, we present evidence that Bcl-xL fosters ATP generation by the mitochondria to fuel high energy needs by neurons, and its contribution to synaptic transmission. We discuss how Bcl-xL might control local and transient activation of caspases in neurons without causing cell death. Consistently, Bcl-xL may contribute to morphological changes, such as sprouting and retractation of axon branches, in the context of CNS plasticity. Regarding degenerative diseases and aging, a better understanding of the numerous roles of the cell death machinery in neurons may have future clinical implications.

scholarly journals Cytoskeletal Changes in Non-Apoptotic Cell Death

2006 ◽  
Vol 49 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Emil Rudolf ◽  
Miroslav Červinka
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Phosphatidyl Serine ◽  
Morphological Features ◽  
Apoptotic Cell Death ◽  
Transient Activation ◽  
Membrane Protrusions ◽  
Nonapoptotic Cell Death ◽  
Dying Cells

Dynamic morphology and cytoskeletal changes in Hep-2 cells exhibiting features of non-apoptotic cell death after treatment with zinc were studied using immunofluorescence microscopy and spectrofluorimetry. Among early morphological changes in treated cells was development of vacuolization, surface blebbing, relatively rapid cell detachment from substratum, cell shrinkage and, in some cases, appearance of membrane protrusions. Staining of microfilaments revealed rapid rearrangement and subsequent loss of F-actin accompanied by changes in the amount and localization of G-actin. The use of specific kinase and caspase inhibitors did not prevent surface blebbing as well as other morphological features in dying cells. Dying cells were only weakly positive for phosphatidyl serine and showed only a transient activation of caspase-9 with no signs of activation of caspase-3. These results suggest the existence of nonapoptotic cell death showing morphological features of both apoptosis and necrosis but, biochemically, resembling some other type of cell death.

Mechanisms of mitochondrial cell death

2021 ◽  
Author(s):  
Shashank Dadsena ◽  
Cristiana Zollo ◽  
Ana J. García-Sáez
Keyword(s):  
Cell Death ◽  
Current Knowledge ◽  
B Cell Lymphoma ◽  
Membrane Lipid ◽  
Membrane Dynamics ◽  
Mitochondrial Outer Membrane ◽  
Intermembrane Space ◽  
Mitochondrial Outer Membrane Permeabilization ◽  
Cell Death Pathways ◽  
Lipid Environment

Mitochondria are double-membrane bound organelles that not only provide energy for intracellular metabolism, but also play a key role in the regulation of cell death. Mitochondrial outer membrane permeabilization (MOMP), allowing the release of intermembrane space proteins like cytochrome c, is considered a point of no return in apoptosis. MOMP is controlled by the proteins of the B-cell lymphoma 2 (BCL-2) family, including pro-and anti-apoptotic members, whose balance determines the decision between cell death and survival. Other factors such as membrane lipid environment, membrane dynamics, and inter-organelle communications are also known to influence this process. MOMP and apoptosis have been acknowledged as immunologically silent. Remarkably, a growing body of evidence indicates that MOMP can engage in various pro-inflammatory signaling functions. In this mini-review, we discuss about our current knowledge on the mechanisms of mitochondrial apoptosis, as well as the involvement of mitochondria in other kinds of programmed cell death pathways.

Oxidative Stress, Ocular Disease and Diabetes Retinopathy

2019 ◽  
Vol 24 (40) ◽  
pp. 4726-4741 ◽  
Author(s):  
Orathai Tangvarasittichai ◽  
Surapon Tangvarasittichai
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Cell Death ◽  
Protein Modification ◽  
Morphological Changes ◽  
Corneal Dystrophy ◽  
Age Related Macular Degeneration ◽  
Ocular Diseases ◽  
Retinal Light Damage ◽  
Age Related

Background: Oxidative stress is caused by free radicals or oxidant productions, including lipid peroxidation, protein modification, DNA damage and apoptosis or cell death and results in cellular degeneration and neurodegeneration from damage to macromolecules. Results: Accumulation of the DNA damage (8HOdG) products and the end products of LPO (including aldehyde, diene, triene conjugates and Schiff’s bases) were noted in the research studies. Significantly higher levels of these products in comparison with the controls were observed. Oxidative stress induced changes to ocular cells and tissues. Typical changes include ECM accumulation, cell dysfunction, cell death, advanced senescence, disarrangement or rearrangement of the cytoskeleton and released inflammatory cytokines. It is involved in ocular diseases, including keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, cataract, age-related macular degeneration, primary open-angle glaucoma, retinal light damage, and retinopathy of prematurity. These ocular diseases are the cause of irreversible blindness worldwide. Conclusions: Oxidative stress, inflammation and autophagy are implicated in biochemical and morphological changes in these ocular tissues. The development of therapy is a major target for the management care of these ocular diseases.

scholarly journals Individual Expression of Hepatitis A Virus 3C Protease Induces Ferroptosis in Human Cells In Vitro

2021 ◽  
Vol 22 (15) ◽  
pp. 7906
Author(s):  
Alexey A. Komissarov ◽  
Maria A. Karaseva ◽  
Marina P. Roschina ◽  
Andrey V. Shubin ◽  
Nataliya A. Lunina ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Proteolytic Enzymes ◽  
Morphological Changes ◽  
Human Cells ◽  
Mitochondrial Potential ◽  
3C Protease ◽  
Wide Range

Regulated cell death (RCD) is a fundamental process common to nearly all living beings and essential for the development and tissue homeostasis in animals and humans. A wide range of molecules can induce RCD, including a number of viral proteolytic enzymes. To date, numerous data indicate that picornaviral 3C proteases can induce RCD. In most reported cases, these proteases induce classical caspase-dependent apoptosis. In contrast, the human hepatitis A virus 3C protease (3Cpro) has recently been shown to cause caspase-independent cell death accompanied by previously undescribed features. Here, we expressed 3Cpro in HEK293, HeLa, and A549 human cell lines to characterize 3Cpro-induced cell death morphologically and biochemically using flow cytometry and fluorescence microscopy. We found that dead cells demonstrated necrosis-like morphological changes including permeabilization of the plasma membrane, loss of mitochondrial potential, as well as mitochondria and nuclei swelling. Additionally, we showed that 3Cpro-induced cell death was efficiently blocked by ferroptosis inhibitors and was accompanied by intense lipid peroxidation. Taken together, these results indicate that 3Cpro induces ferroptosis upon its individual expression in human cells. This is the first demonstration that a proteolytic enzyme can induce ferroptosis, the recently discovered and actively studied type of RCD.

scholarly journals Predicting Responses to Checkpoint Inhibitors in Lymphoma: Are We Up to the Standards of Solid Tumors?

2020 ◽  
Vol 14 ◽  
pp. 117955492097636
Author(s):  
Ah-Reum Jeong ◽  
Edward D Ball ◽  
Aaron Michael Goodman
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
B Cell ◽  
Solid Tumors ◽  
Cell Lymphoma ◽  
Checkpoint Inhibitors ◽  
B Cell Lymphoma ◽  
Hematologic Malignancies ◽  
Checkpoint Blockade ◽  
Programmed Cell Death 1

Treatment of cancer has transformed with the introduction of checkpoint inhibitors. However, the majority of solid tumor patients do not respond to checkpoint blockade. In contrast, the response rate to programmed cell death 1 (PD-1) blockade in relapsed/refractory classical Hodgkin lymphoma (cHL) is 65% to 84% which is the highest among all cancers. Currently, checkpoint inhibitors are only approved for cHL and primary mediastinal B-cell lymphoma as the responses to single-agent checkpoint blockade in other hematologic malignancies is disappointingly low. Various established biomarkers such as programmed cell death 1 ligand 1 (PD-L1) protein surface expression, mismatch repair (MMR) status, and tumor mutational burden (TMB) are routinely used in clinical decision-making in solid tumors. In this review, we will explore these biomarkers in the context of hematologic malignancies. We review characteristic 9p24.1 structural alteration in cHL and primary mediastinal B-cell lymphoma (PMBCL) as a basis for response to PD-1 inhibition, as well as the role of antigen presentation pathways. We also explore the reported frequencies of MMR deficiency in various hematologic malignancies and investigate TMB as a predictive marker.

scholarly journals Molecular mechanisms of cell death in neurological diseases

2021 ◽  
Author(s):  
Diane Moujalled ◽  
Andreas Strasser ◽  
Jeffrey R. Liddell
Keyword(s):  
Cell Death ◽  
Neurodegenerative Diseases ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
Neurological Diseases ◽  
Treatment Strategies ◽  
Current Treatment ◽  
Response To Therapy ◽  
Signalling Cascades ◽  
The Brain

AbstractTightly orchestrated programmed cell death (PCD) signalling events occur during normal neuronal development in a spatially and temporally restricted manner to establish the neural architecture and shaping the CNS. Abnormalities in PCD signalling cascades, such as apoptosis, necroptosis, pyroptosis, ferroptosis, and cell death associated with autophagy as well as in unprogrammed necrosis can be observed in the pathogenesis of various neurological diseases. These cell deaths can be activated in response to various forms of cellular stress (exerted by intracellular or extracellular stimuli) and inflammatory processes. Aberrant activation of PCD pathways is a common feature in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, resulting in unwanted loss of neuronal cells and function. Conversely, inactivation of PCD is thought to contribute to the development of brain cancers and to impact their response to therapy. For many neurodegenerative diseases and brain cancers current treatment strategies have only modest effect, engendering the need for investigations into the origins of these diseases. With many diseases of the brain displaying aberrations in PCD pathways, it appears that agents that can either inhibit or induce PCD may be critical components of future therapeutic strategies. The development of such therapies will have to be guided by preclinical studies in animal models that faithfully mimic the human disease. In this review, we briefly describe PCD and unprogrammed cell death processes and the roles they play in contributing to neurodegenerative diseases or tumorigenesis in the brain. We also discuss the interplay between distinct cell death signalling cascades and disease pathogenesis and describe pharmacological agents targeting key players in the cell death signalling pathways that have progressed through to clinical trials.

scholarly journals Inhibition of mitochondrial carrier homolog 2 (MTCH2) suppresses tumor invasion and enhances sensitivity to temozolomide in malignant glioma

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Qiuyun Yuan ◽  
Wanchun Yang ◽  
Shuxin Zhang ◽  
Tengfei Li ◽  
Mingrong Zuo ◽  
...  
Keyword(s):  
Cell Death ◽  
Malignant Glioma ◽  
Aerobic Glycolysis ◽  
Underlying Mechanism ◽  
Bioinformatic Analysis ◽  
Mitochondrial Outer Membrane ◽  
Invasion Pathways ◽  
Western Blots ◽  
Mitochondrial Functions ◽  
Dependent Cell

Abstract Background Malignant glioma exerts a metabolic shift from oxidative phosphorylation (OXPHOs) to aerobic glycolysis, with suppressed mitochondrial functions. This phenomenon offers a proliferation advantage to tumor cells and decrease mitochondria-dependent cell death. However, the underlying mechanism for mitochondrial dysfunction in glioma is not well elucidated. MTCH2 is a mitochondrial outer membrane protein that regulates mitochondrial metabolism and related cell death. This study aims to clarify the role of MTCH2 in glioma. Methods Bioinformatic analysis from TCGA and CGGA databases were used to investigate the association of MTCH2 with glioma malignancy and clinical significance. The expression of MTCH2 was verified from clinical specimens using real-time PCR and western blots in our cohorts. siRNA-mediated MTCH2 knockdown were used to assess the biological functions of MTCH2 in glioma progression, including cell invasion and temozolomide-induced cell death. Biochemical investigations of mitochondrial and cellular signaling alternations were performed to detect the mechanism by which MTCH2 regulates glioma malignancy. Results Bioinformatic data from public database and our cohort showed that MTCH2 expression was closely associated with glioma malignancy and poor patient survival. Silencing of MTCH2 expression impaired cell migration/invasion and enhanced temozolomide sensitivity of human glioma cells. Mechanistically, MTCH2 knockdown may increase mitochondrial OXPHOs and thus oxidative damage, decreased migration/invasion pathways, and repressed pro-survival AKT signaling. Conclusion Our work establishes the relationship between MTCH2 expression and glioma malignancy, and provides a potential target for future interventions.

Tetrazolium Salt and Electron-Microscopic Studies of Cellular Degeneration and Necrosis in the Interdigital Areas of the Developing Chick Limb

1971 ◽  
Vol 8 (1) ◽  
pp. 229-251
Author(s):  
S. P. HAMMAR ◽  
N. K. MOTTET
Keyword(s):  
Cell Death ◽  
Enzyme Activity ◽  
Succinate Dehydrogenase ◽  
Hind Limb ◽  
Morphological Changes ◽  
Morphological Evidence ◽  
Tetrazolium Salt ◽  
Limb Buds ◽  
Cellular Degeneration ◽  
Intracellular Digestion

Cellular degeneration and necrosis were studied in the interdigital areas of developing hind limb buds of normal chick embryos by means of enzyme-specific tetrazolium salts and electron microscopy. Using succinic acid as a substrate and the tetrazolium salt, nitro blue tetrazolium, succinate dehydrogenase was specifically demonstrated via a colour reaction in which degenerating and necrotic cells--those with no enzyme activity--did not stain, while those with enzyme activity stained deeply blue-black. The interdigital cells exhibited near absent levels of succinate dehydrogenase as early as stage 26-27, one to two days prior to when morphological evidence of degeneration and necrosis was present. It was postulated that the mechanism of cell death resulted from decreased activity and/or loss of strategic cellular enzymes such as succinate dehydrogenase, with a subsequent fall in the cellular adenosine triphosphate (ATP) level and a resultant compromise in vital cellular processes, eventually leading to cell death. The evidence indicated that ‘biochemical degeneration’ occurred prior to morphological changes in cells. The ultrastructural events of degenerating and necrotic cells were also studied. Most ‘dying’ cells observed had already been phagocytosed and were observed in various stages of degeneration. The degenerating cells exhibited both nuclear and cytoplasmic changes. There was evidence of active intracellular digestion within the phagocytes. Numerous lysosomes were observed within these cells, and some appeared fused with the digestive vacuole's membranes. The origin of the phagocytes was not determined. No definite information was obtained concerning the utility of cellular degeneration and necrosis in the interdigital areas of the hind limb buds. It appeared to be at least partially causal in separation of the digits.

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