scholarly journals Platelets express adaptor proteins of the extrinsic apoptosis pathway and can activate caspase-8

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244848
Author(s):  
Nadine Goelz ◽  
Julia J. M. Eekels ◽  
Milica Pantic ◽  
Christoph T. Kamber ◽  
Oliver Speer ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Caspase 3 ◽  
Human Platelets ◽  
Death Domain ◽  
Extrinsic Pathway ◽  
Apoptosis Pathway ◽  
Extrinsic Apoptosis ◽  
Necrosis Factor

Background Apoptotic pathways in platelets are important for their survival and function. Platelet apoptosis may be involved in the pathogenesis of immune thrombocytopenia (ITP), an autoimmune-mediated disease. In contrast to the intrinsic apoptosis pathway, not much is known about the extrinsic pathway mechanisms in platelets. Objectives To investigate the expression of proteins involved in the extrinsic apoptosis pathway, including the death receptors, adaptor and regulator proteins in human platelets. To determine a possible trigger of the extrinsic apoptosis pathway in platelets. Methods To investigate the expression of key markers of the extrinsic pathway we used targeted immunofluorescence and flow cytometry assays. To study their expression and interaction we performed Western blotting and co-immunoprecipitation. Treated platelets with different apoptosis triggers were subjected to flow cytometry. Results We could identify the protein expression of the pro-apoptotic proteins TRADD (Tumor Necrosis Factor Receptor type 1- Associated DEATH Domain protein), TRAF2/5, (TNF Associated Factor) and DEDAF (Death Effector Domain- Associated Factor), FADD (Fas-Associated protein with death domain) as well as the anti-apoptotic proteins DJ-1 (Deglycase 1) and c-FLIP in human platelets. ABT-737 treatment induced a disruption in the co-localization of DJ-1 with FADD. Platelets treated with ABT-737 showed an activation in caspase-3 and -8. The exposure to TNF (Tumor Necrosis Factor), FasL (Fas ligand), and TWEAK or to plasma derived from ITP patients, did not lead to changes in caspase-3 and -8 activation in platelets. Conclusions Human platelets express some proteins of the extrinsic apoptosis pathway which can be modulated only by ABT-737 treatment. However so far, no other apoptosis trigger or interaction with an external receptor have been yet identified.

scholarly journals LIGHT, a Member of the Tumor Necrosis Factor Ligand Superfamily, Prevents Tumor Necrosis Factor-α-mediated Human Primary Hepatocyte Apoptosis, but Not Fas-mediated Apoptosis

2002 ◽  
Vol 277 (51) ◽  
pp. 50054-50061 ◽  
Author(s):  
Hideki Matsui ◽  
Yukiko Hikichi ◽  
Isamu Tsuji ◽  
Takao Yamada ◽  
Yasushi Shintani
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Time Course ◽  
Caspase 3 ◽  
Nuclear Factor Κb ◽  
Caspase 8 ◽  
Death Domain ◽  
Human Primary Hepatocytes ◽  
Induced Apoptosis ◽  
Necrosis Factor

LIGHT is a member of tumor necrosis factor (TNF) superfamily, and its receptors have been identified as lymphotoxin-β receptor (LTβR) and the herpesvirus entry mediator (HVEM)/ATAR/TR2, both of which lack the cytoplasmic sequence termed the “death domain.” The present study has demonstrated that LIGHT inhibits TNFα-mediated apoptosis of human primary hepatocytes sensitized by actinomycin D (ActD), but not Fas- or TRAIL-mediated apoptosis. Furthermore, LIGHT does not prevent some cell lines such as HepG2 or HeLa from undergoing ActD/TNFα-induced apoptosis. This protective effect requires LIGHT pretreatment at least 3 h prior to ActD sensitization. LIGHT stimulates nuclear factor-κB (NF-κB)-dependent transcriptional activity in human hepatocytes like TNFα. The time course of NF-κB activation after LIGHT administration is similar to that of the pretreatment required for the anti-apoptotic effect of LIGHT. LIGHT inhibits caspase-3 processing on the apoptotic protease cascade in TNFα-mediated apoptosis but not Fas-mediated apoptosis. In addition, increased caspase-3 and caspase-8 activities in ActD/TNFα-treated cells are effectively blocked by LIGHT pretreatment. However, LIGHT does not change the expression of TNFRp55, TNFRp75, and Fas. These results indicate that LIGHT may act as an anti-apoptotic agent against TNFα-mediated liver injury by blocking the activation of both caspase-3 and caspase-8.

scholarly journals A20 Inhibits Tumor Necrosis Factor (TNF) Alpha-Induced Apoptosis by Disrupting Recruitment of TRADD and RIP to the TNF Receptor 1 Complex in Jurkat T Cells

2002 ◽  
Vol 22 (17) ◽  
pp. 6034-6045 ◽  
Author(s):  
Kai-Li He ◽  
Adrian T. Ting
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Zinc Finger Protein ◽  
Tumor Necrosis Factor Receptor ◽  
Death Domain ◽  
Apoptotic Pathway ◽  
Apoptosis Pathway ◽  
Enhanced Sensitivity ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT Tumor necrosis factor receptor 1 (TNFR1) can trigger distinct signaling pathways leading to either the activation of NF-κB transcription factors or apoptosis. NF-κB activation results in the expression of antiapoptotic genes that inhibit the apoptosis pathway that is activated in parallel. However, the molecular mechanism of this inhibition remains poorly characterized. We have isolated a Jurkat T-cell mutant that exhibits enhanced sensitivity to TNF-induced apoptosis as a result of a deficiency in I-κB kinase γ (IKKγ)/NEMO, an essential component of the IKK complex and NF-κB pathway. We show here that the zinc finger protein A20 is an NF-κB-inducible gene that can protect the IKKγ-deficient cells from TNF-induced apoptosis by disrupting the recruitment of the death domain signaling molecules TRADD and RIP to the receptor signaling complex. Our study, together with reports on the role of other antiapoptotic proteins such as c-FLIP and c-IAP, suggests that, in order to ensure an effective shutdown of the apoptotic pathway, TNF induces multiple NF-κB-dependent genes that inhibit successive steps in the TNFR1 death signaling pathway.

scholarly journals The α and β Subunits of IκB Kinase (IKK) Mediate TRAF2-Dependent IKK Recruitment to Tumor Necrosis Factor (TNF) Receptor 1 in Response to TNF

2001 ◽  
Vol 21 (12) ◽  
pp. 3986-3994 ◽  
Author(s):  
Anne Devin ◽  
Yong Lin ◽  
Shoji Yamaoka ◽  
Zhiwei Li ◽  
Michael Karin ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Leucine Zipper ◽  
Nuclear Translocation ◽  
Ring Finger ◽  
Tnf Receptor ◽  
Death Domain ◽  
Iκb Kinase ◽  
Cytokine Tumor Necrosis Factor ◽  
Necrosis Factor

ABSTRACT The activation of IκB kinase (IKK) is a key step in the nuclear translocation of the transcription factor NF-κB. IKK is a complex composed of three subunits: IKKα, IKKβ, and IKKγ (also called NEMO). In response to the proinflammatory cytokine tumor necrosis factor (TNF), IKK is activated after being recruited to the TNF receptor 1 (TNF-R1) complex via TNF receptor-associated factor 2 (TRAF2). We found that the IKKα and IKKβ catalytic subunits are required for IKK-TRAF2 interaction. This interaction occurs through the leucine zipper motif common to IKKα, IKKβ, and the RING finger domain of TRAF2, and either IKKα or IKKβ alone is sufficient for the recruitment of IKK to TNF-R1. Importantly, IKKγ is not essential for TNF-induced IKK recruitment to TNF-R1, as this occurs efficiently in IKKγ-deficient cells. Using TRAF2−/− cells, we demonstrated that the TNF-induced interaction between IKKγ and the death domain kinase RIP is TRAF2 dependent and that one possible function of this interaction is to stabilize the IKK complex when it interacts with TRAF2.

scholarly journals Tumor Necrosis Factor (TNF) Receptor Expression Determines Keratinocyte Fate upon Stimulation with TNF-Like Weak Inducer of Apoptosis

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xuening Wang ◽  
Dan Cheng ◽  
Guanglei Hu ◽  
Lili Liang ◽  
Fei Tan ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Receptor Expression ◽  
Structural Basis ◽  
Tnf Receptor ◽  
Death Domain ◽  
Independent Manner ◽  
Normal Keratinocytes ◽  
Apoptosis Protein ◽  
Necrosis Factor

The interaction between tumor necrosis factor- (TNF-) like weak inducer of apoptosis (TWEAK) and fibroblast growth factor-inducible 14 (Fn14) regulates the fate of keratinocytes, depending on the relative expression of TNF receptor (TNFR) 1 or TNFR2. However, the precise mechanism underlying this TWEAK-mediated regulation remains unclear. The aim of this study was to provide comprehensive insight into the roles of Fn14, TNFR1/2, and other relevant molecules in the fate of keratinocytes. Further, we sought to elucidate the structural basis for the interaction of TWEAK and Fn14 in regulating cellular outcomes. Normal keratinocytes (mainly expressing TNFR1) and TNFR2-overexpressing keratinocytes were stimulated with TWEAK. Through immunoprecipitation and Western blotting of keratinocyte lysates, we elucidated the associations between Fn14, TNFR-associated factor 2 (TRAF2), cellular inhibitor of apoptosis protein 1 (cIAP1), and TNFR1/2 molecules. Additionally, we found that TRAF2 exhibited binding to Fn14, cIAP1, and TNFR1/2. Our data suggest that TWEAK induces apoptosis in normal keratinocytes and proliferation in TNFR2-overexpressing keratinocytes in a TNF-α-independent manner; however, inhibition of TRAF2 appears to reverse this effect. Interestingly, the interaction between TWEAK and Fn14 increased TNFR1-associated death domain protein and caspase-8 expression in normal keratinocytes and promoted cytoplasmic import of cIAP1 in TNFR2-overexpressing keratinocytes. In conclusion, we found that the Fn14-TRAF2-TNFR signaling axis mediates TWEAK’s regulation of the fate of keratinocytes, possibly in a manner involving the TNF-α-independent TNFR signal transduction.

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