scholarly journals Lack of Correlation between Activation of Jun–NH2-terminal Kinase and Induction of Apoptosis after Detachment of Epithelial Cells

1997 ◽  
Vol 139 (4) ◽  
pp. 1017-1023 ◽  
Author(s):  
Asim Khwaja ◽  
Julian Downward
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Programmed Cell Death ◽  
Mdck Cells ◽  
Dominant Negative ◽  
Signaling Proteins ◽  
Direct Role ◽  
Related Stress ◽  
Induced Apoptosis ◽  
Jnk Activation

Detachment of epithelial cells from the extracellular matrix leads to induction of programmed cell death, a process that has been termed “anoikis.” It has been reported recently that detachment of MDCK cells from matrix results in activation of Jun–NH2-terminal kinases (JNKs) and speculated that these stress activated protein kinases play a causal role in the induction of anoikis (Frisch, S.M., K. Vuori, D. Kelaita, and S. Sicks. 1996. J. Cell Biol. 135:1377–1382). We report here that although JNK is activated by detachment of normal MDCK cells, study of cell lines expressing activated signaling proteins usually controlled by Ras shows that stimulation of JNK fails to correlate with induction of anoikis. Activated phosphoinositide 3-OH kinase and activated PKB/Akt protect MDCK cells from detachment-induced apoptosis without suppressing JNK activation. Conversely, activated Raf and dominant negative SEK1, a JNK kinase, attenuate detachment-induced JNK activation without protecting from apoptosis. zVAD-fmk, a peptide inhibitor of caspases, prevents MDCK cell anoikis without affecting JNK activation. p38, a related stress-activated kinase, is also stimulated by detachment from matrix, but inhibition of this kinase with SB 203580 does not protect from anoikis. It is therefore unlikely that either JNK or p38 play a direct role in detachment-induced programmed cell death in epithelial cells.

Prevention of TNF-α-induced apoptosis in polyamine-depleted IEC-6 cells is mediated through the activation of ERK1/2

2004 ◽  
Vol 286 (3) ◽  
pp. G479-G490 ◽  
Author(s):  
Sujoy Bhattacharya ◽  
Ramesh M. Ray ◽  
Leonard R. Johnson
Keyword(s):  
Epithelial Cells ◽  
Cytochrome C ◽  
Critical Role ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Cytochrome C Release ◽  
Erk Phosphorylation ◽  
Tnf Α ◽  
Induced Apoptosis ◽  
Jnk Activation

It has been documented that polyamines play a critical role in the regulation of apoptosis in intestinal epithelial cells. We have recently reported that protection from TNF-α/cycloheximide (CHX)-induced apoptosis in epithelial cells depleted of polyamines is mediated through the inactivation of a proapoptotic mediator, JNK. In this study, we addressed the involvement of the MAPK pathway in the regulation of apoptosis after polyamine depletion of IEC-6 cells. Polyamine depletion by α-difluromethylornithine (DFMO) resulted in the sustained activation of ERK in response to TNF-α/CHX treatment. Pretreatment of polyamine-depleted IEC-6 cells with a cell membrane-permeable MEK1/2 inhibitor, U-0126, significantly inhibited TNF-α/CHX-induced ERK phosphorylation and significantly increased DNA fragmentation, JNK activity, and caspase-3 activity in response to TNF-α/CHX. Moreover, the dose dependency of U-0126-mediated inhibition of TNF-α/ CHX-induced ERK phosphorylation correlated with the reversal of the antiapoptotic effect of DFMO. IEC-6 cells expressing constitutively active MEK1 had decreased TNF-α/CHX-induced JNK phosphorylation and were significantly protected from apoptosis. Conversely, a dominant-negative MEK1 resulted in high basal activation of JNK, cytochrome c release, and spontaneous apoptosis. Polyamine depletion of the dominant-negative MEK1 cells did not prevent JNK activation or cytochrome c release and failed to confer protection from both TNF-α/CHX and camptothecin-induced apoptosis. Finally, expression of a dominant-negative mutant of JNK significantly protected IEC-6 cells from TNF-α/CHX-induced apoptosis. These data indicate that polyamine depletion results in the activation of ERK, which inhibits JNK activation and protects cells from apoptosis.

scholarly journals Streptococcus pneumoniae-Induced Caspase 6-Dependent Apoptosis in Lung Epithelium

2004 ◽  
Vol 72 (9) ◽  
pp. 4940-4947 ◽  
Author(s):  
Bernd Schmeck ◽  
Ralph Gross ◽  
Phillipe Dje N′Guessan ◽  
Andreas C. Hocke ◽  
Sven Hammerschmidt ◽  
...  
Keyword(s):  
Cell Death ◽  
Streptococcus Pneumoniae ◽  
Epithelial Cells ◽  
Programmed Cell Death ◽  
Caspase 3 ◽  
Lung Epithelium ◽  
Bronchial Epithelial ◽  
Caspase 6 ◽  
Induced Apoptosis ◽  
Increased Activity

ABSTRACT Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia and one of the most common causes of death due to infectious diseases in industrialized countries. Lung epithelium lines the airways and constitutes the first line of innate defense against respiratory pathogens. Little is known about the molecular interaction of pneumococci with lung epithelial cells. Apoptosis of lung epithelium is involved in some bacterial lung infections. In this study different pneumococcal strains specifically induced either apoptotic or necrotic death of human alveolar and bronchial epithelial cells. Pneumococcus-induced apoptosis did not depend on the virulence factors pneumolysin and H2O2. Apoptotic cells showed increased activity of caspases 6, 8, and 9 but not increased activity of caspase 3. Moreover, programmed cell death could be strongly reduced by a caspase 6 inhibitor and a pan-caspase inhibitor. Inhibitors of calpain and chymotrypsin- and trypsin-like proteases also reduced pneumococcus-induced apoptosis. Furthermore, pneumococcus-infected human alveolar epithelial cells showed Bid cleavage and reduced levels of Bcl2 and Bax. Overexpression of Bcl2 in these cells reduced apoptosis significantly. Thus, pneumococci induced apoptosis of human alveolar and bronchial epithelial cells. Programmed cell death was executed by caspase 6 and noncaspase proteases, but not by caspase 3, and could be blocked by overexpression of Bcl2.

scholarly journals Lack of a role for Jun kinase and AP-1 in Fas-induced apoptosis.

1997 ◽  
Vol 17 (1) ◽  
pp. 170-181 ◽  
Author(s):  
J M Lenczowski ◽  
L Dominguez ◽  
A M Eder ◽  
L B King ◽  
C M Zacharchuk ◽  
...  
Keyword(s):  
Cell Death ◽  
Interleukin 2 ◽  
Dominant Negative ◽  
Jurkat Cells ◽  
Direct Result ◽  
Cross Linking ◽  
Activation Pathway ◽  
Jun Kinase ◽  
Induced Apoptosis ◽  
Jnk Activation

Cross-linking of Fas (CD95) induces apoptosis, a response that has been reported to depend upon the Ras activation pathway. Since many examples of apoptosis have been reported to involve AP-1 and/or the AP-1-activation pathway. Since many examples of apoptosis have been reported to involve AP-1 and/or the AP-1-activating enzyme Jun kinase (JNK), downstream effectors of Ras or Ras-like small GTP-binding proteins, we evaluated the role of these molecules in Fas-mediated apoptosis. Although cross-linking of Fas on Jurkat T cells did result in JNK activation, increased activity was observed relatively late, being detectable only after 60 min of stimulation. Expression of a dominant negative form of SEK1 that blocked Fas-mediated induction of JNK activity had no effect on Fas-mediated apoptosis. Furthermore, maximally effective concentrations of anti-Fas did not cause JNK activation if apoptosis was blocked by a cysteine protease inhibitor, suggesting that under these conditions, activation of JNK may be secondary to the stress of apoptosis rather than a direct result of Fas engagement. Despite the activation of JNK, there was no induction of AP-1 activity as determined by gel shift assay or induction of an AP-1-responsive reporter. The lack of a requirement for AP-1 induction in Fas-mediated death was further substantiated with Jurkat cells that were stably transfected with a dominant negative cJun, TAM-67. While TAM-67 effectively prevented AP-1-dependent transcription of both the interleukin-2 and cJun genes, it had no effect on Fas-induced cell death, even at limiting levels of Fas signaling. Thus, induction of JNK activity in Jurkat cells by ligation of Fas at levels sufficient to cause cell death is likely a result, rather than a cause, of the apoptotic response, and AP-1 function is not required for Fas-induced apoptosis.

scholarly journals Apoptosis in Hydra: function of HyBcl-2 like 4 and proteins of the transmembrane BAX inhibitor motif (TMBIM) containing family

2019 ◽  
Vol 63 (6-7) ◽  
pp. 259-270 ◽  
Author(s):  
Mina Motamedi ◽  
Laura Lindenthal ◽  
Anita Wagner ◽  
Margherita Kemper ◽  
Jasmin Moneer ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Programmed Cell Death ◽  
Kinase Inhibitor ◽  
Apoptotic Cell ◽  
Family Members ◽  
Sequence Comparisons ◽  
Induced Apoptosis ◽  
Related Proteins

Mechanisms of programmed cell death differ between animals, plants and fungi. In animals, apoptotic cell death depends on caspases and Bcl-2 family proteins. These protein families are only found in multicellular animals, including cnidarians, insects and mammals. In contrast, members of the TMBIM-family of transmembrane proteins are conserved across all eukaryotes. Sequence comparisons of cell death related proteins between phyla indicate strong conservation of the genes involved. However, often it is not known whether this is paralleled by conservation of function. Here we present the first study to support an anti-apoptotic function of Bcl-2 like proteins in the cnidarian Hydra within a physiological context. We used transgenic Hydra expressing GFP-tagged HyBcl-2-like 4 protein in epithelial cells. The protein was localised to mitochondria and able to protect Hydra epithelial cells from apoptosis induced by either the PI(3) kinase inhibitor wortmannin or by starvation. Moreover, we identified members of the TMBIM-family in Hydra including HyBax-Inhibitor-1, HyLifeguard-1a and -1b and HyLifeguard 4. Expressing these TMBIM-family members in Hydra and human HEK cells, we found HyBax-inhibitor-1 protein localised to ER-membranes and HyLifeguard-family members localised to the plasma membrane and Golgi-vesicles. Moreover, HyBax-inhibitor-1 protected human cells from camptothecin induced apoptosis. This work illustrates that the investigated Bcl-2- and TMBIM-family members represent evolutionarily conserved mitochondrial, ER, Golgi and plasma membrane proteins with anti-apoptotic functions. The participation of ER and Golgi proteins in the regulation of programmed cell death might be a very ancient feature.

scholarly journals Atypical Protein Kinase C Is Involved in the Evolutionarily Conserved Par Protein Complex and Plays a Critical Role in Establishing Epithelia-Specific Junctional Structures

2001 ◽  
Vol 152 (6) ◽  
pp. 1183-1196 ◽  
Author(s):  
Atsushi Suzuki ◽  
Tomoyuki Yamanaka ◽  
Tomonori Hirose ◽  
Naoyuki Manabe ◽  
Keiko Mizuno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Polarity ◽  
Protein Complex ◽  
Mdck Cells ◽  
Critical Role ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Surface Polarity ◽  
C Elegans ◽  
Evolutionarily Conserved

We have previously shown that during early Caenorhabditis elegans embryogenesis PKC-3, a C. elegans atypical PKC (aPKC), plays critical roles in the establishment of cell polarity required for subsequent asymmetric cleavage by interacting with PAR-3 [Tabuse, Y., Y. Izumi, F. Piano, K.J. Kemphues, J. Miwa, and S. Ohno. 1998. Development (Camb.). 125:3607–3614]. Together with the fact that aPKC and a mammalian PAR-3 homologue, aPKC-specific interacting protein (ASIP), colocalize at the tight junctions of polarized epithelial cells (Izumi, Y., H. Hirose, Y. Tamai, S.-I. Hirai, Y. Nagashima, T. Fujimoto, Y. Tabuse, K.J. Kemphues, and S. Ohno. 1998. J. Cell Biol. 143:95–106), this suggests a ubiquitous role for aPKC in establishing cell polarity in multicellular organisms. Here, we show that the overexpression of a dominant-negative mutant of aPKC (aPKCkn) in MDCK II cells causes mislocalization of ASIP/PAR-3. Immunocytochemical analyses, as well as measurements of paracellular diffusion of ions or nonionic solutes, demonstrate that the biogenesis of the tight junction structure itself is severely affected in aPKCkn-expressing cells. Furthermore, these cells show increased interdomain diffusion of fluorescent lipid and disruption of the polarized distribution of Na+,K+-ATPase, suggesting that epithelial cell surface polarity is severely impaired in these cells. On the other hand, we also found that aPKC associates not only with ASIP/PAR-3, but also with a mammalian homologue of C. elegans PAR-6 (mPAR-6), and thereby mediates the formation of an aPKC-ASIP/PAR-3–PAR-6 ternary complex that localizes to the apical junctional region of MDCK cells. These results indicate that aPKC is involved in the evolutionarily conserved PAR protein complex, and plays critical roles in the development of the junctional structures and apico-basal polarization of mammalian epithelial cells.

BH3-only proteins are essential initiators of programmed cell death and stress-induced apoptosis in normal and cancer cells

2008 ◽  
Vol 6 (9) ◽  
pp. 6
Author(s):  
A. Strasser ◽  
A. Villunger ◽  
P. Bouillet ◽  
E.M. Michalak ◽  
L.A. O'Reilly ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Cancer Cells ◽  
Induced Apoptosis

Increased cytochrome P-450 2E1 expression sensitizes hepatocytes to c-Jun-mediated cell death from TNF-α

2002 ◽  
Vol 282 (2) ◽  
pp. G257-G266 ◽  
Author(s):  
Hailing Liu ◽  
Brett E. Jones ◽  
Cynthia Bradham ◽  
Mark J. Czaja
Keyword(s):  
Cell Death ◽  
Oxidant Stress ◽  
Nuclear Factor Κb ◽  
Dominant Negative ◽  
Tnf Α ◽  
Cyp2e1 Expression ◽  
Factor Α ◽  
Jnk Activation ◽  
Cytochrome P 450 ◽  
Necrosis Factor

The mechanisms underlying hepatocyte sensitization to tumor necrosis factor-α (TNF-α)-mediated cell death remain unclear. Increases in hepatocellular oxidant stress such as those that occur with hepatic overexpression of cytochrome P-450 2E1 (CYP2E1) may promote TNF-α death. TNF-α treatment of hepatocyte cell lines with differential CYP2E1 expression demonstrated that overexpression of CYP2E1 converted the hepatocyte TNF-α response from proliferation to apoptotic and necrotic cell death. Death occurred despite the presence of increased levels of nuclear factor-κB transcriptional activity and was associated with increased lipid peroxidation and GSH depletion. CYP2E1-overexpressing hepatocytes had increased basal and TNF-α-induced levels of c-Jun NH2-terminal kinase (JNK) activity, as well as prolonged JNK activation after TNF-α stimulation. Sensitization to TNF-α-induced cell death by CYP2E1 overexpression was inhibited by antioxidants or adenoviral expression of a dominant-negative c-Jun. Increased CYP2E1 expression sensitized hepatocytes to TNF-α toxicity mediated by c-Jun and overwhelming oxidative stress. The chronic increase in intracellular oxidant stress created by CYP2E1 overexpression may serve as a mechanism by which hepatocytes are sensitized to TNF-α toxicity in liver disease.

scholarly journals Abrogation of ER stress-induced apoptosis of alveolar epithelial cells by angiotensin 1–7

2013 ◽  
Vol 305 (1) ◽  
pp. L33-L41 ◽  
Author(s):  
Bruce D. Uhal ◽  
Hang Nguyen ◽  
MyTrang Dang ◽  
Indiwari Gopallawa ◽  
Jing Jiang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Er Stress ◽  
Cathepsin D ◽  
Primary Cultures ◽  
A549 Cells ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Induced Apoptosis ◽  
Jnk Activation

Earlier work showed that apoptosis of alveolar epithelial cells (AECs) in response to endogenous or xenobiotic factors is regulated by autocrine generation of angiotensin (ANG) II and its counterregulatory peptide ANG1–7. Mutations in surfactant protein C (SP-C) induce endoplasmic reticulum (ER) stress and apoptosis in AECs and cause lung fibrosis. This study tested the hypothesis that ER stress-induced apoptosis of AECs might also be regulated by the autocrine ANGII/ANG1–7 system of AECs. ER stress was induced in A549 cells or primary cultures of human AECs with the proteasome inhibitor MG132 or the SP-C BRICHOS domain mutant G100S. ER stress activated the ANGII-generating enzyme cathepsin D and simultaneously decreased the ANGII-degrading enzyme ACE-2, which normally generates the antiapoptotic peptide ANG1–7. TAPI-2, an inhibitor of ADAM17/TACE, significantly reduced both the activation of cathepsin D and the loss of ACE-2. Apoptosis of AECs induced by ER stress was measured by assays of mitochondrial function, JNK activation, caspase activation, and nuclear fragmentation. Apoptosis induced by either MG132 or the SP-C BRICHOS mutant G100S was significantly inhibited by the ANG receptor blocker saralasin and was completely abrogated by ANG1–7. Inhibition by ANG1–7 was blocked by the specific mas antagonist A779. These data show that ER stress-induced apoptosis is mediated by the autocrine ANGII/ANG1–7 system in human AECs and demonstrate effective blockade of SP-C mutation-induced apoptosis by ANG1–7. They also suggest that therapeutic strategies aimed at administering ANG1–7 or stimulating ACE-2 may hold potential for the management of ER stress-induced fibrotic lung disorders.

scholarly journals T-2 mycotoxin induced apoptosis in broiler’s liver tissue

2018 ◽  
Vol 27 (1) ◽  
pp. 9-16
Author(s):  
Piret Hussar ◽  
Tõnu Järveots ◽  
Lazo Pendovski ◽  
Katerina Blagoevska ◽  
Trpe Ristoski ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Liver Tissue ◽  
Immunohistochemical Staining ◽  
Mammalian Cells ◽  
Gallus Domesticus ◽  
Gallus Gallus Domesticus ◽  
Histopathological Changes ◽  
Induced Apoptosis ◽  
Multicellular Organisms

Apoptosis is a process of programmed cell death that occurs in multicellular organisms. As T-2 toxin is known to induce apoptosis in mammalian cells, the aim of the present experiment was to study the toxic effect of T-2 on chicken liver tissue using apoptosis-related antibodies p21 and p53 which are involved in the p53/p21-mediated apoptotic signalling pathway. The experiment was conducted on fourteen 40-day-old broilers (Gallus gallus domesticus) who were divided into control and T-2 toxin groups. For the T-2 toxin group, T-2 toxin (Sigma, Germany) was dissolved in water and given per os for three consecutive days. The material of the liver was taken 24 hours after the last application. The specimens were fixed with 10% formalin and embedded into paraffin; slices 5 μm in thickness were cut followed by immunohistochemical staining with polyclonal primary antibodies p21 and p53 (Abcam, UK) according to the manufacturer’s guidelines (IHC kit, Abcam, UK). Strong expression of p21 and p53 found in hepatocytes, endotheliocytes and around blood vessels together with large tissue destructions in T-2 toxin group birds’ liver indicates apoptosis and histopathological changes in liver tissue during T-2 mycotoxicosis.

scholarly journals Growth Arrest-Specific Gene 6 (Gas6)/Adhesion Related Kinase (Ark) Signaling Promotes Gonadotropin-Releasing Hormone Neuronal Survival via Extracellular Signal-Regulated Kinase (ERK) and Akt

1999 ◽  
Vol 13 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Melissa P. Allen ◽  
Chan Zeng ◽  
Kristina Schneider ◽  
Xiaoyan Xiong ◽  
Mary Kay Meintzer ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Neuronal Migration ◽  
Neuronal Development ◽  
Mek Inhibitor ◽  
Specific Gene ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Gnrh Neurons ◽  
Induced Apoptosis

Abstract We identified Ark, the mouse homolog of the receptor tyrosine kinase Axl (Ufo, Tyro7), in a screen for novel factors involved in GnRH neuronal migration by using differential-display PCR on cell lines derived at two windows during GnRH neuronal development. Ark is expressed in Gn10 GnRH cells, developed from a tumor in the olfactory area when GnRH neurons are migrating, but not in GT1–7 cells, derived from a tumor in the forebrain when GnRH neurons are postmigratory. Since Ark (Axl) signaling protects from programmed cell death in fibroblasts, we hypothesized that it may play an antiapoptotic role in GnRH neurons. Gn10 (Ark positive) GnRH cells were more resistant to serum withdrawal-induced apoptosis than GT1–7 (Ark negative) cells, and this effect was augmented with the addition of Gas6, the Ark (Axl) ligand. Gas6/Ark stimulated the extracellular signal-regulated kinase, ERK, and the serine-threonine kinase, Akt, a downstream component of the phosphoinositide 3-kinase (PI3-K) pathway. To determine whether ERK or Akt activation is required for the antiapoptotic effects of Gas6/Ark in GnRH neurons, cells were serum starved in the absence or presence of Gas6, with or without inhibitors of ERK and PI3-K signaling cascades. Gas6 rescued Gn10 cells from apoptosis, and this effect was blocked by coincubation of the cells with the mitogen-activated protein/ERK kinase (MEK) inhibitor, PD98059, or wortmannin (but not rapamycin). These data support an important role for Gas6/Ark signaling via the ERK and PI3-K (via Akt) pathways in the protection of GnRH neurons from programmed cell death across neuronal migration.

Sign in / Sign up

Export Citation Format

Share Document