scholarly journals Mechanisms of necroptosis in T cells

2011 ◽  
Vol 208 (4) ◽  
pp. 633-641 ◽  
Author(s):  
Irene L. Ch’en ◽  
Jennifer S. Tsau ◽  
Jeffery D. Molkentin ◽  
Masaaki Komatsu ◽  
Stephen M. Hedrick
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Lymphoproliferative Disease ◽  
Cell Populations ◽  
Caspase 8 ◽  
Related Protein ◽  
Cyclophilin D ◽  
Serine Threonine Kinase ◽  
Programmed Necrosis ◽  
Threonine Kinase

Cell populations are regulated in size by at least two forms of apoptosis. More recently, necroptosis, a parallel, nonapoptotic pathway of cell death, has been described, and this pathway is invoked in the absence of caspase 8. In caspase 8–deficient T cells, necroptosis occurs as the result of antigen receptor–mediated activation. Here, through a genetic analysis, we show that necroptosis in caspase 8–deficient T cells is related neither to the programmed necrosis as defined by the requirement for mitochondrial cyclophilin D nor to autophagy as defined by the requirement for autophagy-related protein 7. Rather, survival of caspase 8–defective T cells can be completely rescued by loss of receptor-interacting serine-threonine kinase (Ripk) 3. Additionally, complementation of a T cell–specific caspase 8 deficiency with a loss of Ripk3 gives rise to lymphoproliferative disease reminiscent of lpr or gld mice. In conjunction with previous work, we conclude that necroptosis in antigen-stimulated caspase 8–deficient T cells is the result of a novel Ripk1- and Ripk3-mediated pathway of cell death.

scholarly journals Death Receptor-Induced Activation of Initiator Caspase 8 Is Antagonized by Serine/Threonine Kinase PAK4

2003 ◽  
Vol 23 (21) ◽  
pp. 7838-7848 ◽  
Author(s):  
Nerina Gnesutta ◽  
Audrey Minden
Keyword(s):  
Cell Death ◽  
Cell Survival ◽  
Intracellular Signaling ◽  
Death Receptor ◽  
Caspase 8 ◽  
Death Domain ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Different Types ◽  
Promote Cell Survival

ABSTRACT Normal cell growth requires a precisely controlled balance between cell death and survival. This involves activation of different types of intracellular signaling cascades within the cell. While some types of signaling proteins regulate apoptosis, or programmed cell death, other proteins within the cell can promote survival. The serine/threonine kinase PAK4 can protect cells from apoptosis in response to several different types of stimuli. As is the case for other members of the p21-activated kinase (PAK) family, one way that PAK4 may promote cell survival is by phosphorylating and thereby inhibiting the proapoptotic protein Bad. This leads in turn to the inhibition of effector caspases such as caspase 3. Here we show that in response to cytokines which activate death domain-containing receptors, such as the tumor necrosis factor and Fas receptors, PAK4 can inhibit the death signal by a different mechanism. Under these conditions, PAK4 inhibits apoptosis early in the caspase cascade, antagonizing the activation of initiator caspase 8. This inhibition, which does not require PAK4's kinase activity, may involve inhibition of caspase 8 recruitment to the death domain receptors. This role in regulating initiator caspases is an entirely novel role for the PAK proteins and suggests a new mechanism by which these proteins promote cell survival.

Abstract 143: A Novel TAK1 Signaling Network Regulating Programmed Necrosis and Myocardial Remodeling

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Qinghang Liu ◽  
Lei Li ◽  
Yi Chen ◽  
Jessica Doan ◽  
Jeffery Molkentin
Keyword(s):  
Heart Failure ◽  
Cell Death ◽  
Cell Survival ◽  
Cardiac Fibrosis ◽  
Signaling Network ◽  
Specific Gene ◽  
Caspase 8 ◽  
Programmed Necrosis ◽  
Genetic Ablation ◽  
Cell Death Pathway

We recently identified a novel signaling molecule, TAK1 (TGFβ-activated kinase 1, also known as MAP3K7), as a key regulator of the hypertrophic signaling network. Importantly, TAK1 is activated in mouse models of heart failure as well as in diseased human myocardium. Here, we defined a previously unidentified, novel role for TAK1 in promoting cardiac cell survival and homeostasis using cardiac-specific gene-targeted mice. Indeed, cardiac-specific ablation of TAK1 in mice using a Cre-LoxP system showed enhanced pathological cardiac remodeling and massive cell death, and these mice gradually developed heart failure and spontaneous death. Remarkably, ablation of TNF receptor 1 (TNFR1) largely rescued the pathological phenotype of TAK1-deficient mice, preventing early lethality and cardiac fibrosis, suggesting that TNFR1 signaling is critical in mediating adverse remodeling and heart failure associated with TAK1 deficiency. Genetic or pharmacological inactivation of TAK1 in cardiomyocytes markedly induced programmed necrosis and apoptosis in response to TNFα. Conversely, overexpression of the constitutively active TAK1 mutant, or TAK1 plus its activator TAB1, protected cardiomyocytes from TNFα-induced cell death. Mechanistically, inactivation of TAK1 promoted formation of the necroptotic cell death complex consisting of RIP1, RIP3, caspase 8, and FADD. Genetic ablation of RIP1, RIP3, caspase 8, or FADD largely blocked TNFα-induced cell death in TAK1-deficient cells, whereas deletion of Bax/Bak or cyclophilin D showed no effects. Further, IKK/NFκB-mediated cell survival signaling was greatly impaired in TAK1-deficient cardiomyocytes. Taken together, our data indicate that TAK1 functions as a critical “molecular switch” in TNFα-induced programmed necrosis in cardiomyocytes, by interacting with the RIP1/3-caspase 8-FADD cell death pathway as well as the IKK-NFκB cell survival pathway. These findings thus define an important TAK1-mediated cardio-protective signaling network in the heart, which may suggest new therapeutic strategies in the treatment of heart disease.

scholarly journals SIRT7 Deacetylates STRAP to Regulate p53 Activity and Stability

2020 ◽  
Vol 21 (11) ◽  
pp. 4122 ◽  
Author(s):  
Miao Yu ◽  
Xiaoyan Shi ◽  
Mengmeng Ren ◽  
Lu Liu ◽  
Hao Qi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Death ◽  
Cell Cycle Arrest ◽  
Creb Binding Protein ◽  
Serine Threonine Kinase ◽  
Receptor Associated Protein ◽  
Threonine Kinase ◽  
P53 Signaling ◽  
Cycle Arrest

Serine-threonine kinase receptor-associated protein (STRAP) functions as a regulator of both TGF-β and p53 signaling that participates in the regulation of cell proliferation and cell death in response to various stresses. Here, we demonstrate that STRAP acetylation plays an important role in p53-mediated cell cycle arrest and apoptosis. STRAP is acetylated at lysines 147, 148, and 156 by the acetyltransferases CREB-binding protein (CBP) and that the acetylation is reversed by the deacetylase sirtuin7 (SIRT7). Hypo- or hyperacetylation mutations of STRAP at lysines 147, 148, and 156 (3KR or 3KQ) influence its activation and stabilization of p53. Moreover, following 5-fluorouracil (5-FU) treatment, STRAP is mobilized from the cytoplasm to the nucleus and promotes STRAP acetylation. Our finding on the regulation of STRAP links p53 with SIRT7 influencing p53 activity and stability.

Functional CD95 ligand and CD95 death-inducing signaling complex in activation-induced cell death and doxorubicin-induced apoptosis in leukemic T cells

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 301-308 ◽  
Author(s):  
Simone Fulda ◽  
Gudrun Strauss ◽  
Eric Meyer ◽  
Klaus-Michael Debatin
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Leukemia Cell Line ◽  
Receptor Interaction ◽  
Caspase 8 ◽  
Drug Induced ◽  
Signaling Complex ◽  
Cd95 Ligand ◽  
Activation Induced Cell Death ◽  
Induced Apoptosis

Abstract Activation-induced cell death (AICD) in T cells is mediated by CD95 ligand (CD95L)/receptor interaction, which has also been implicated in apoptosis induction by some anticancer agents. In this article we show that both anti-CD3-triggering (AICD) and doxorubicin treatment led to the production of a functionally active CD95L in the CD3+/T-cell receptor-positive (TCR+) T leukemia cell line H9. CD95L-expressing H9 cells killed CD95-sensitive J16 or CEM target cells, but not CD95-resistant CEM or J16 cells overexpressing dominant negative FADD (J16/FADD-DN). By immunoprecipitation, CD95L was physically bound to CD95, suggesting that AICD and doxorubicin-induced apoptosis involve CD95L-mediated CD95 aggregation, thereby triggering the CD95 death pathway. CD95 aggregation was associated with the recruitment of FADD and caspase-8 to the CD95 receptor to form the CD95 death-inducing signaling complex (DISC), resulting in caspase-8 activation and cleavage of the effector caspase-3 and PARP. Blocking of the CD95L/receptor interaction by antagonistic antibodies to CD95 or to CD95L also blocked AICD and inhibited the early phase of doxorubicin-induced apoptosis, though cell death induced by doxorubicin eventually proceeded in a CD95-independent manner. These findings may explain some conflicting data on the role of death receptor systems in drug-induced apoptosis. Thus, in cells with an inducible CD95 receptor/ligand system, drug-induced apoptosis may be mediated by CD95L-initiated DISC formation and activation of downstream effector programs similar to AICD in T cells. (Blood. 2000;95:301-308)

scholarly journals The Caspase 8 Inhibitor c-FLIPL Modulates T-Cell Receptor-Induced Proliferation but Not Activation-Induced Cell Death of Lymphocytes

2002 ◽  
Vol 22 (15) ◽  
pp. 5419-5433 ◽  
Author(s):  
Susanne M. A. Lens ◽  
Takao Kataoka ◽  
Karen A. Fortner ◽  
Antoine Tinel ◽  
Isabel Ferrero ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
T Cell Receptor ◽  
Death Receptor ◽  
Cell Receptor ◽  
Caspase 8 ◽  
Activation Induced Cell Death

ABSTRACT The caspase 8 inhibitor c-FLIPL can act in vitro as a molecular switch between cell death and growth signals transmitted by the death receptor Fas (CD95). To elucidate its function in vivo, transgenic mice were generated that overexpress c-FLIPL in the T-cell compartment (c-FLIPL Tg mice). As anticipated, FasL-induced apoptosis was inhibited in T cells from the c-FLIPL Tg mice. In contrast, activation-induced cell death of T cells in c-FLIPL Tg mice was unaffected, suggesting that this deletion process can proceed in the absence of active caspase 8. Accordingly, c-FLIPL Tg mice differed from Fas-deficient mice by showing no accumulation of B220+ CD4− CD8− T cells. However, stimulation of T lymphocytes with suboptimal doses of anti-CD3 or antigen revealed increased proliferative responses in T cells from c-FLIPL Tg mice. Thus, a major role of c-FLIPL in vivo is the modulation of T-cell proliferation by decreasing the T-cell receptor signaling threshold.

Targeting the Serine-Threonine Kinase PIM2: Implications in IL-6 Mediated Survival in Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3401-3401
Author(s):  
Jayakumar R Nair ◽  
Tyger L Howell ◽  
Justin Caserta ◽  
Carmen M Baldino ◽  
Gerald Fetterly ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Drug Resistance ◽  
Cell Death ◽  
Plasma Cells ◽  
Serine Threonine Kinase ◽  
Myeloma Cells ◽  
Threonine Kinase ◽  
Equity Ownership ◽  
Microarray Expression

Abstract Despite major advances in chemotherapy, multiple myeloma remains incurable and in need of new therapies that target novel pathways. Insufficient understanding of the molecular pathways that regulate survival in myeloma is a major impediment towards designing better therapies to prolong survival in patients or even cure the disease. This necessitates the identification of new protein targets that are crucial for the growth and survival of multiple myeloma. Just like normal plasma cells, MM cells also depend on their interactions with bone marrow stromal cells (BMSC) for survival and production of essential growth factors. We have previously shown that MM cells interact with dendritic cells (DC) in the microenvironment and in vitro can stimulate DC to produce IL-6 (ASH2010#132, ASH2011 #147, ASH2012#722). Our recent publications show that when MM cells are not in direct contact with DC, the IL-6 produced by DC can protect MM cells against dexamethasone induced cell death, while neutralizing the IL-6 with antibodies can reverse that effect (Nair et al., 2011). Unfortunately, exactly how this survival response is mediated in MM is not very clear. PIM2, a serine threonine kinase, part of the proto-oncogene group of PIM kinases has been implicated in survival in several types of cancers including prostate cancer and multiple myeloma. In our lab, microarray gene expression analysis of publicly available datasets (Figure 1) show a trend towards increased expression of PIM2 in plasma cells from myeloma patients (left panel), and significantly in the poor prognosis subgroup MAF (Zhan et al., 2006) (right panel). For the first time we show that IL-6 produced by DC may be protecting myeloma cells by up regulating PIM2 and inactivating a major protein translation inhibitor 4EBP1, which also happens to be a PIM2 target. We show that silencing PIM2 with siRNA down regulates PIM2 activity and reverses the inactivation of 4EBP1, while the latter is known to cause cell death in myeloma. We also demonstrate that neutralizing IL-6 in MM cells that either don’t produce IL-6 on their own (MM.1S) or those that do (U266), abrogates extraneous DC-IL6 ability to induce PIM2 and its downstream target 4EBP1. Recombinant IL-6 also provided similar induction of PIM2 in myeloma and increased 4EBP1 phosphorylation, which was again reversed by neutralizing the antibody against IL-6. In myeloma patients, the use of dexamethasone in frontline therapies is often complicated by the ability of the bone marrow environment to produce IL-6 that not only induce increased proliferation of MM but also help resist dexamethasone mediated cell death in myeloma. Interestingly, when we used a novel PIM2 inhibitor, JP_11646 (kindly provided by Jasco Pharmaceuticals, LLC), it not only arrested IL-6 induced proliferation even at sub-lethal doses, but also prevented IL-6 mediated rescue of myeloma cells (Figure 2). This suggests that PIM2 might be a major player in IL-6 mediated drug resistance in myeloma and targeting it may help to subvert IL-6 mediated survival in myeloma. Through RT-PCR and westerns, we also show that IL-6 modulates PIM2 expression and activity resulting in increased 4EBP1 phosphorylation (Figure 3). This was abrogated when PIM2 activity was inhibited by JP_11646 (Figure 3). We also present data that suggests IL-6 via PIM2 may be regulating other anti-apoptotic molecules downstream of IL-6 receptors including MCL-1, that is vital to MM survival. Developing PIM2 targeted therapies provides an exciting opportunity to affect the myeloma tumor microenvironment where MM induced IL-6 production from BM could be inducing drug resistance. Figure 1: Microarray expression ofPIM2 in myeloma and MAF Figure 1:. Microarray expression ofPIM2 in myeloma and MAF Figure 2: PIM2 inhibition abrogates IL-6 induced MM proliferation (A) and protection (B). Figure 2:. PIM2 inhibition abrogates IL-6 induced MM proliferation (A) and protection (B). Figure 3: Inhibiting PIM2 activity prevents PIM2 induced phosphorylation of 4EBP1 by IL-6 in myeloma Figure 3:. Inhibiting PIM2 activity prevents PIM2 induced phosphorylation of 4EBP1 by IL-6 in myeloma Disclosures Caserta: Jasco Pharmaceuticals LLC: Equity Ownership. Baldino:Jasco Pharmaceuticals LLC: Equity Ownership.

Functional CD95 ligand and CD95 death-inducing signaling complex in activation-induced cell death and doxorubicin-induced apoptosis in leukemic T cells

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 301-308 ◽  
Author(s):  
Simone Fulda ◽  
Gudrun Strauss ◽  
Eric Meyer ◽  
Klaus-Michael Debatin
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Leukemia Cell Line ◽  
Receptor Interaction ◽  
Caspase 8 ◽  
Drug Induced ◽  
Signaling Complex ◽  
Cd95 Ligand ◽  
Activation Induced Cell Death ◽  
Induced Apoptosis

Activation-induced cell death (AICD) in T cells is mediated by CD95 ligand (CD95L)/receptor interaction, which has also been implicated in apoptosis induction by some anticancer agents. In this article we show that both anti-CD3-triggering (AICD) and doxorubicin treatment led to the production of a functionally active CD95L in the CD3+/T-cell receptor-positive (TCR+) T leukemia cell line H9. CD95L-expressing H9 cells killed CD95-sensitive J16 or CEM target cells, but not CD95-resistant CEM or J16 cells overexpressing dominant negative FADD (J16/FADD-DN). By immunoprecipitation, CD95L was physically bound to CD95, suggesting that AICD and doxorubicin-induced apoptosis involve CD95L-mediated CD95 aggregation, thereby triggering the CD95 death pathway. CD95 aggregation was associated with the recruitment of FADD and caspase-8 to the CD95 receptor to form the CD95 death-inducing signaling complex (DISC), resulting in caspase-8 activation and cleavage of the effector caspase-3 and PARP. Blocking of the CD95L/receptor interaction by antagonistic antibodies to CD95 or to CD95L also blocked AICD and inhibited the early phase of doxorubicin-induced apoptosis, though cell death induced by doxorubicin eventually proceeded in a CD95-independent manner. These findings may explain some conflicting data on the role of death receptor systems in drug-induced apoptosis. Thus, in cells with an inducible CD95 receptor/ligand system, drug-induced apoptosis may be mediated by CD95L-initiated DISC formation and activation of downstream effector programs similar to AICD in T cells. (Blood. 2000;95:301-308)

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