The Canonical Intrinsic Mitochondrial Death Pathway Has a Non-apoptotic Role in Signaling Lens Cell Differentiation

The mitochondrial cell death pathway is known for its role in signaling apoptosis. Here, we describe a novel function for the mitochondrial cell death pathway in signaling initiation of differentiation in the developing lens. Most remarkably, we induced lens cell differentiation by short-term exposure of lens epithelial cells to the apoptogen staurosporine. Activation of apoptosis-related pathways induced lens epithelial cells to express differentiation-specific markers and to undergo morphogenetic changes that led to formation of the lens-like structures known as lentoids. The fact that multiple stages of differentiation are expressed at a single stage of development in the embryonic lens made it possible to precisely determine the timing of expression of proteins associated with the apoptotic pathway. We discovered that there was high expression in the lens equatorial epithelium (the region of the lens in which differentiation is initiated) of pro-apoptotic molecules such as Bax and Bcl-xS and release of cytochrome c from mitochondria. Furthermore, we found significant caspase-3-like activity in the equatorial epithelium, yet this activity was far lower than that associated with lens cell apoptosis. These apoptotic pathways are likely regulated by the concurrent expression of prosurvival molecules, including Bcl-2 and Bcl-xL; phosphorylation of Bad; and high expression of inhibitor of apoptosis proteins chicken IAP1, IAP3, and survivin. This finding suggests that prosurvival pathways allow pro-apoptotic molecules to function as molecular switches in the differentiation process without tipping the balance toward apoptosis. We call this process apoptosis-related Bcl-2- and caspase-dependent (ABC) differentiation.

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A role for c-myc in chemically induced renal-cell death.

Molecular and Cellular Biology ◽

10.1128/mcb.17.11.6755 ◽

1997 ◽

Vol 17 (11) ◽

pp. 6755-6764 ◽

Cited By ~ 23

Author(s):

Y Zhan ◽

J L Cleveland ◽

J L Stevens

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Apoptotic Cell ◽

Tubular Damage ◽

Transactivation Domain ◽

Apoptotic Pathway ◽

Toxicant Exposure ◽

Renal Epithelial Cells ◽

Cell Death Pathway

A variety of genes, including c-myc, are activated by chemical toxicants in vivo and in vitro. Although enforced c-myc expression induces apoptosis after withdrawing survival factors, it is not clear if activation of the endogenous c-myc gene is an apoptotic signal after toxicant exposure. The renal tubular epithelium is a target for many toxicants. c-myc expression is activated by tubular damage. In quiescent LLC-PK1 renal epithelial cells, c-myc but not max or mad mRNA is induced by the nephrotoxicant S-(1,2-dichlorovinyl)-L-cysteine (DCVC). The kinetics of DCVC-induced c-myc expression and apoptosis suggested an association between cell death and prolonged activation of c-myc expression after toxicant exposure. Accordingly, prolonged activation of an estrogen receptor-Myc fusion construct, but not a construct in which a c-Myc transactivation domain had been deleted, was sufficient to induce apoptosis in LLC-PK1 cells. Moreover, under conditions in which necrosis was the predominant cell death pathway caused by DCVC in parental cells, overexpressing c-myc biased the cell death pathway toward apoptosis. DCVC also induced ornithine decarboxylase (odc) mRNA and activated the odc promoter. Activation of the odc promoter by DCVC required consensus c-Myc-Max binding sites in odc intron 1. Inhibiting ODC activity with alpha-difluoromethylornithine delayed DCVC-induced cell death. Therefore, odc is a target gene in the DCVC apoptotic pathway involving c-myc activation and contributes to apoptosis. Finally, a structurally related cytotoxic but nongenotoxic analog of DCVC did not induce c-myc and did not activate the odc promoter or induce apoptosis. The data support the hypothesis that activation of apoptotic cell death in quiescent renal epithelial cells involves induction of c-myc. This is the first study to demonstrate that c-myc induction by a specific nephrotoxicant leads to gene activation and cell death.

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Mitomycin C-Induced Cell Death in Mouse Lens Epithelial Cells

Ophthalmic Research ◽

10.1159/000063880 ◽

2002 ◽

Vol 34 (4) ◽

pp. 213-219 ◽

Cited By ~ 10

Author(s):

Hyun-Kyung Park ◽

Kwang-Won Lee ◽

Jun-Sub Choi ◽

Choun-Ki Joo

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Mitomycin C ◽

Lens Epithelial Cells ◽

Mouse Lens

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Helicobacter hepaticusCytolethal Distending Toxin Causes Cell Death in Intestinal Epithelial Cells via Mitochondrial Apoptotic Pathway

Helicobacter ◽

10.1111/j.1523-5378.2010.00749.x ◽

2010 ◽

Vol 15 (2) ◽

pp. 98-107 ◽

Cited By ~ 30

Author(s):

Namal P. M. Liyanage ◽

Karoline C. Manthey ◽

Rohana P. Dassanayake ◽

Charles A. Kuszynski ◽

Gregory G. Oakley ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Intestinal Epithelial ◽

Apoptotic Pathway ◽

Mitochondrial Apoptotic Pathway

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Lens Epithelial Cells Express CD95 and CD95 Ligand Treatment Induces Cell death and DNA Fragmentation in Vitro

European Journal of Ophthalmology ◽

10.1177/112067210301300301 ◽

2003 ◽

Vol 13 (3) ◽

pp. 241-245 ◽

Cited By ~ 5

Author(s):

A. Hueber ◽

C.D. Eichholtz ◽

N. Kociok ◽

J.M. Esser ◽

P.J. Esser

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Dna Fragmentation ◽

Lens Epithelial Cells ◽

Cd95 Ligand

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Short-Wavelength Blue Light Contributes to Pyroptosis of Human Lens Epithelial Cells (hLECs) by Caspase-1-GSDMD Signalling Axis Activation

10.21203/rs.3.rs-44771/v1 ◽

2020 ◽

Author(s):

Zhaowei Song ◽

Xiaohui Wang ◽

Huazhang Li ◽

Ying Sun ◽

Kexin Liu ◽

...

Keyword(s):

Flow Cytometry ◽

Cell Death ◽

Epithelial Cells ◽

Blue Light ◽

Short Wavelength ◽

Human Lens ◽

Lens Epithelial Cells ◽

Expression Levels ◽

Human Lens Epithelial Cells ◽

Caspase 1

Abstract Backgroud: To examine the effects of short-wavelength blue light (SWBL) on cultured human lens epithelial cells (hLECs). The nosogenesis of cataracts after SWBL exposure was discussed. Methods: HLE-B3 hLECs were divided into 3 groups randomly: A: normal control group, which consisted of hLECs cultured in the dark; B: the caspase-1 inhibitor group; and C: the SWBL exposure group. After the SWBL (2500 lux) irradiation (for 8, 16, 24, and 32 h), the caspase-1 and gasdermin D (GSDMD) expression levels in HLE-B3 hLECs were examined using ELISA, immunofluorescence, and Western blotting analyses. Double-positive staining of HLE-B3 hLECs for activated and inhibited caspase-1 was used to confirm pyroptosis in hLECs by flow cytometry. Results: SWBL can cause cell death in HLE-B3 hLECs, but a caspase-1 inhibitor suppressed cell death. The flow cytometry results also confirmed the does-dependent of short-wavelength blue light irradiation on pyroptotic death of hLECs. Caspase-1 and GSDMD expression levels of all hLECs groups changed with short-wavelength blue light exposure times (8, 16, 24, and 32 h) and were higher in groups B and C than group A. The immunofluorescence results demonstrated that the expression of GSDMD-N was higher in the cell membrane in both the B and C groups than in the A group.Conclusion: The data indicate that SWBL induces pyroptotic programmed cell death by activation of the GSDMD signalling axis in HLE-B3 hLECs. These results provide new insights into the exploitation of new candidates for the prevention of cataracts.

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Involvement of Calpain 2 in Ionomycin-induced Cell Death in Cultured Mouse Lens Epithelial Cells

Current Eye Research ◽

10.3109/02713683.2011.577264 ◽

2011 ◽

Vol 36 (10) ◽

pp. 930-936

Author(s):

Takeshi Nakajima ◽

Thomas R. Shearer ◽

Mitsuyoshi Azuma

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Lens Epithelial Cells ◽

Calpain 2 ◽

Mouse Lens

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EspC, an Autotransporter Protein Secreted by EnteropathogenicEscherichia coli, Causes Apoptosis and Necrosis through Caspase and Calpain Activation, Including Direct Procaspase-3 Cleavage

mBio ◽

10.1128/mbio.00479-16 ◽

2016 ◽

Vol 7 (3) ◽

Cited By ~ 16

Author(s):

Antonio Serapio-Palacios ◽

Fernando Navarro-Garcia

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Intracellular Calcium ◽

Serine Protease ◽

Focal Adhesion ◽

Apoptotic Pathway ◽

Mitochondrial Apoptotic Pathway ◽

Calpain Activation ◽

Functional Relationships ◽

Apoptosis And Necrosis

ABSTRACTEnteropathogenicEscherichia coli(EPEC) has the ability to antagonize host apoptosis during infection through promotion and inhibition of effectors injected by the type III secretion system (T3SS), but the total number of these effectors and the overall functional relationships between these effectors during infection are poorly understood. EspC produced by EPEC cleaves fodrin, paxillin, and focal adhesion kinase (FAK), which are also cleaved by caspases and calpains during apoptosis. Here we show the role of EspC in cell death induced by EPEC. EspC is involved in EPEC-mediated cell death and induces both apoptosis and necrosis in epithelial cells. EspC induces apoptosis through the mitochondrial apoptotic pathway by provoking (i) a decrease in the expression levels of antiapoptotic protein Bcl-2, (ii) translocation of the proapoptotic protein Bax from cytosol to mitochondria, (iii) cytochromecrelease from mitochondria to the cytoplasm, (iv) loss of mitochondrial membrane potential, (v) caspase-9 activation, (vi) cleavage of procaspase-3 and (vii) an increase in caspase-3 activity, (viii) PARP proteolysis, and (ix) nuclear fragmentation and an increase in the sub-G1population. Interestingly, EspC-induced apoptosis was triggered through a dual mechanism involving both independent and dependent functions of its EspC serine protease motif, the direct cleavage of procaspase-3 being dependent on this motif. This is the first report showing a shortcut for induction of apoptosis by the catalytic activity of an EPEC protein. Furthermore, this atypical intrinsic apoptosis appeared to induce necrosis through the activation of calpain and through the increase of intracellular calcium induced by EspC. Our data indicate that EspC plays a relevant role in cell death induced by EPEC.IMPORTANCEEspC, an autotransporter protein with serine protease activity, has cytotoxic effects on epithelial cells during EPEC infection. EspC causes cytotoxicity by cleaving fodrin, a cytoskeletal actin-associated protein, and focal adhesion proteins (i.e., FAK); interestingly, these proteins are also cleaved during apoptosis and necrosis. Here we show that EspC is able to cause cell death, which is characterized by apoptosis: by dissecting the apoptotic pathway and considering that EspC is translocated by an injectisome, we found that EspC induces the mitochondrial apoptotic pathway. Remarkably, EspC activates this pathway by two distinct mechanisms—either by using or not using its serine protease motif. Thus, we show for the first time that this serine protease motif is able to cleave procaspase-3, thereby reaching the terminal stages of caspase cascade activation leading to apoptosis. Furthermore, this overlapped apoptosis appears to potentiate cell death through necrosis, where EspC induces calpain activation and increases intracellular calcium.

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Epilepsy and Apoptosis Pathways

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/sj.jcbfm.9600149 ◽

2005 ◽

Vol 25 (12) ◽

pp. 1557-1572 ◽

Cited By ~ 119

Author(s):

David C Henshall ◽

Roger P Simon

Keyword(s):

Cell Death ◽

Neuronal Death ◽

Apoptotic Cell ◽

Death Receptor ◽

Apoptotic Pathway ◽

Apoptosis Pathway ◽

Cell Death Pathway ◽

Pathway Function ◽

Apoptosis Pathways ◽

Molecular Machinery

Epilepsy is a common, chronic neurologic disorder characterized by recurrent unprovoked seizures. Experimental modeling and clinical neuroimaging of patients has shown that certain seizures are capable of causing neuronal death. Such brain injury may contribute to epileptogenesis, impairments in cognitive function or the epilepsy phenotype. Research into cell death after seizures has identified the induction of the molecular machinery of apoptosis. Here, the authors review the clinical and experimental evidence for apoptotic cell death pathway function in the wake of seizure activity. We summarize work showing intrinsic (mitochondrial) and extrinsic (death receptor) apoptotic pathway function after seizures, activation of the caspase and Bcl-2 families of cell death modulators and the acute and chronic neuropathologic impact of intervening in these molecular cascades. Finally, we describe evolving data on nonlethal roles for these proteins in neuronal restructuring and cell excitability that have implications for shaping the epilepsy phenotype. This review highlights the work to date on apoptosis pathway signaling during seizure-induced neuronal death and epileptogenesis, and speculates on how emerging roles in brain remodeling and excitability have enriched the number of therapeutic strategies for protection against seizure-damage and epileptogenesis.

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