ATP and adenosine prevent via different pathways the activation of caspases in apoptotic AKR-2B fibroblasts

Hoppe, Jürgen; Hoppe, Viviane; Sachinidis, Agapios

doi:10.1038/sj.cdd.4400518

Cited by 7 publications

(3 citation statements)

References 19 publications

(33 reference statements)

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“…31 Multiple signaling pathways, which interfere with the activation of a caspase-3 like activity, have been identified. 29,31,32 Here we show that although all caspases are expressed in AKR-2B cells, caspase-3 is the main executioner caspase; caspase-7 protein is not detectable. Furthermore, we demonstrated the formation of three different sized complexes in response to serum deprivation.…”

Section: Introductionmentioning

confidence: 99%

Formation of noncanonical high molecular weight caspase-3 and -6 complexes and activation of caspase-12 during serum starvation induced apoptosis in AKR-2B mouse fibroblasts

et al. 2002

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Apoptosis is mainly brought about by the activation of caspases, a protease family with unique substrate selectivity. In mammals, different complexes like the DISC complex or the apoptosome complexes have been delineated leading to the cleavage and thus activation of the executioner caspases. Although caspase-3 is the main executioner caspase in apoptosis induced by serum starvation in AKR-2B fibroblasts as demonstrated by affinity labeling with YVK(-bio)D.aomk and partial purification of cytosolic extracts by high performance ion exchange chromatography, its activation is apparently caused by a noncanonical pathway: (1) Expression of CrmA, an inhibitor of caspase-8, failed to suppress apoptosis; (2) There was no formation of high molecular weight complexes of Apaf-1 indicative for its activation. Furthermore no cleavage of caspase-9 was observed. But surprisingly, gelfiltration experiments revealed the distribution of caspase-3 and -6 into differently sized high molecular weight complexes during apoptosis. Though the apparent molecular weights of the complexes containing caspase-3 (600 kD for apoptosome and 250 kD for microapoptosome) are in accordance with recently published data, the activity profiles differ strikingly. In AKR-2B cells caspase-3 is mainly recovered as uncomplexed enzyme and in much lower levels in the apoptosomes. Remarkably, the 600 kD and 250 kD complexes containing activated caspase-3 were devoid of Apaf-1 and cytochrome c. In addition a new 450 kD complex containing activated caspase-6 was found that is clearly separated from the caspase-3 containing complexes. Furthermore, we disclose for the first time the activation of caspase-12 in response to serum starvation. Activated caspase-12 is detectable as non-complexed free enzyme in the cytosol.

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Section: Introductionmentioning

confidence: 99%

Formation of noncanonical high molecular weight caspase-3 and -6 complexes and activation of caspase-12 during serum starvation induced apoptosis in AKR-2B mouse fibroblasts

et al. 2002

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“…At the mRNA level, all P2 receptors are expressed in hMSC, except P2X 2 , where they display different actions pertaining to cell proliferation, migration, or differentiation [27,28]. In other cell types, nucleotide-stimulated P2Y receptors are linked to the regulation of apoptosis and their activation has been shown to prevent cell death [29][30][31][32]. Depending on the cell type, ATP activates specifically different P2Y receptors and transduces prosurvival signals via diverse signaling pathways such as ERK/ MAPK, PI3K/PKB, or cAMP/PKA.…”

Section: Introductionmentioning

confidence: 99%

Adenosine Triphosphate Prevents Serum Deprivation-Induced Apoptosis in Human Mesenchymal Stem Cells via Activation of the MAPK Signaling Pathways

et al. 2014

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Human mesenchymal stem cells (hMSC) are multipotent cells derived from various sources including adipose and placental tissues as well as bone marrow. Owing to their regenerative and immunomodulatory properties, their use as a potential therapeutic tool is being extensively tested. However, one of the major hurdles in using cell-based therapy is the use of fetal bovine serum that can trigger immune responses, viral and prion diseases. The development of a culture medium devoid of serum while preserving cell viability is therefore a major challenge. In this study, we demonstrated that adenosine triphosphate (ATP) restrained serum deprivation-induced cell death in hMSC by preventing caspases 3/7 activation and modulating ERK1/2 and p38 MAPK signaling pathways. We also showed that serum deprivation conditions triggered dephosphorylation of the proapoptotic protein Bad leading to cell death. Adjunction of ATP restored the phosphorylation state of Bad. Furthermore, ATP significantly modulated the expression of proapoptopic and antiapoptotic genes, in favor of an antiapoptotic profile expression. Finally, we established that hMSC released a high amount of ATP in the extracellular medium when cultured in a serum-free medium. Collectively, our results demonstrate that ATP favors hMSC viability in serum deprivation conditions. Moreover, they shed light on the cardinal role of the MAPK pathways, ERK1/2 and p38 MAPK, in promoting hMSC survival. STEM CELLS 2015;33:211-218

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“…We have shown previously that all caspases are expressed in AKR-2B cells with the exception of caspase-7. Caspase-3 is the main executioner caspase during apoptosis induced by serum deprivation or after anisomycin treatment [20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Mutations dislocate caspase‐12 from the endoplasmatic reticulum to the cytosol

Hoppe

2004

FEBS Letters

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Mouse AKR-2B cells express two forms of caspase-12: the full-length form coding for a protein of 47.8 kDa and a new splice variant of 40.2 kDa which is devoid of the CARD domain. In addition, three point mutations were disclosed: I/L-15, E/D-46 and P/L-105. A major portion of the two protein variants was found in the cytosol. Immunofluorescence studies showed an even distribution of caspase-12 within the cell, indicative for a cytoplasmatic localization. Transfection of AKR-2B cells with wild-type caspase-12 showed a colocalization of this protein with the endoplasmic reticulum (ER). Unlike mouse embryonal fibroblasts (MEF) which contain wild-type caspase-12, AKR-2B cells were largely resistant against treatment with the endoplasmatic reticulum stressing reagents brefeldin and tunicamycin. In AKR-2B cells, cytoplasmatic caspase-12 is bound to high molecular weight complexes of >1000 kDa [Cell Death Differ. 9 (2001) 125] and serum depletion leads to cleavage and detachment of caspase-12 from this high molecular weight complex. Cleavage of caspase-12 and -3 occurred almost simultaneously reaching a maximum 3-5 h after serum deprivation at which time also maximum apoptosis is found. Analysis of caspase-12 cleavage in vitro in comparison with fragmentation in vivo suggests that during death in AKR-2B cells induced by starvation, cleavage was brought about by caspase-3 at positions D24 and D94. Thus, mutated caspase-12 is differently integrated in signaling pathways of cell death and has lost its function as initiator caspase upon ER-stress. Instead, it is turned into a substrate of effector caspases. The implication of these findings in the pathological phenotype of ARK-2B mice is discussed.

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ATP and adenosine prevent via different pathways the activation of caspases in apoptotic AKR-2B fibroblasts

Cited by 7 publications

References 19 publications

Formation of noncanonical high molecular weight caspase-3 and -6 complexes and activation of caspase-12 during serum starvation induced apoptosis in AKR-2B mouse fibroblasts

Formation of noncanonical high molecular weight caspase-3 and -6 complexes and activation of caspase-12 during serum starvation induced apoptosis in AKR-2B mouse fibroblasts

Adenosine Triphosphate Prevents Serum Deprivation-Induced Apoptosis in Human Mesenchymal Stem Cells via Activation of the MAPK Signaling Pathways

Mutations dislocate caspase‐12 from the endoplasmatic reticulum to the cytosol

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