Programmed cell death is affected in the novel mouse mutant Fused toes (Ft)

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2601-2607 ◽  
Author(s):  
F. van der Hoeven ◽  
T. Schimmang ◽  
A. Volkmann ◽  
M.G. Mattei ◽  
B. Kyewski ◽  
...  

We have identified a novel dominant mouse mutant that is characterised by fused toes on the fore limbs and a thymic hyperplasia, in heterozygous animals. Homozygosity of the mutation leads to malformation of the developing brain, lost of the genetic control of left-right asymmetry and to death around day 10 of development. Analysis of both limb development and induction of apoptosis in immature thymocytes in vitro suggest that programmed cell death is affected by the mutation. Since the mutation was caused via a transgene insertion we were able to map it to the D region on mouse chromosome 8. So far, no mutation that affects programmed cell death has been mapped to this chromosome. Thus, this mutation will allow the identification of a novel gene involved in programmed cell death during mammalian development.

2013 ◽  
Vol 4 (3) ◽  
pp. 259-275 ◽  
Author(s):  
Michael J. Morgan ◽  
Zheng-gang Liu

AbstractProgrammed cell death is the process by which an individual cell in a multicellular organism commits cellular ‘suicide’ to provide a long-term benefit to the organism. Thus, programmed cell death is important for physiological processes such as development, cellular homeostasis, and immunity. Importantly, in this process, the cell is not eliminated in response to random events but in response to an intricate and genetically defined set of internal cellular molecular events or ‘program’. Although the apoptotic process is generally very well understood, programmed cell death that occurs with a necrotic-like phenotype has been much less studied, and it is only within the past few years that the necrotic program has begun to be elucidated. Originally, programmed necrosis was somewhat dismissed as a nonphysiological phenomenon that occurs in vitro. Recent in vivo studies, however, suggest that regulated necrosis is an authentic classification of cell death that is important in mammalian development and other physiological processes, and programmed necrosis is now considered a significant therapeutic target in major pathological processes as well. Although the RIP1-RIP3-dependent necrosome complex is recognized as being essential for the execution of many instances of programmed necrosis, other downstream and related necrotic molecules and pathways are now being characterized. One of the current challenges is understanding how and under what conditions these pathways are linked together.


Blood ◽  
1996 ◽  
Vol 87 (11) ◽  
pp. 4746-4753 ◽  
Author(s):  
A Cayota ◽  
F Vuillier ◽  
G Gonzalez ◽  
G Dighiero

Oxidative stress has been proposed to be involved in the immunologic defeat observed in effector calls of the immune system as well as in lymphocyte cell death and viral replication in human immunodeficiency virus (HIV)-infected patients. Because thiol-containing antioxidants such as N-acetyl-L-cysteine have been shown to have beneficial effects on CD4+ lymphocyte survival and to inhibit programmed cell death and HIV-1 replication, they may play a role in therapeutic strategies of this disease. In this work we have studied the cellular thiol levels and the affect of in vitro antioxidant treatment of purified CD4+ lymphocytes from HIV-infected patients, and correlated these parameters to proliferative responses and programmed cell death. We show that CD4+ lymphocytes from HIV-infected patients display impaired proliferative responses and a significant decrease in cellular thiol levels, indicating a disturbed redox status. Interestingly, antioxidant treatment succeeded to restore defective proliferative responses to CD3- mediated activation in 8 of 11 patients (high antioxidant responders). In contrast to high responders, patients failing to respond to antioxidant treatment (low antioxidant responders), were characterized by an abnormal ratio of apoptotic cells, which was not affected by N- acetyl-L-cysteine and/or 2-beta-mercaptoethanol preincubation. These results demonstrate for the first time that antioxidant treatment is able to revert the impaired proliferative activity of CD4 cells from HIV-infected patients and could help designing therapeutic strategies with antioxidant drugs. However, this action is not observed in cells undergoing programmed cell death.


2012 ◽  
Vol 129 (1-4) ◽  
pp. 38-50 ◽  
Author(s):  
Ryo Aizawa ◽  
Atsushi Yamada ◽  
Dai Suzuki ◽  
Tadahiro Iimura ◽  
Hidetoshi Kassai ◽  
...  

2012 ◽  
Vol 209 (6) ◽  
pp. 1201-1217 ◽  
Author(s):  
Tadashi Yokosuka ◽  
Masako Takamatsu ◽  
Wakana Kobayashi-Imanishi ◽  
Akiko Hashimoto-Tane ◽  
Miyuki Azuma ◽  
...  

Programmed cell death 1 (PD-1) is a negative costimulatory receptor critical for the suppression of T cell activation in vitro and in vivo. Single cell imaging elucidated a molecular mechanism of PD-1–mediated suppression. PD-1 becomes clustered with T cell receptors (TCRs) upon binding to its ligand PD-L1 and is transiently associated with the phosphatase SHP2 (Src homology 2 domain–containing tyrosine phosphatase 2). These negative costimulatory microclusters induce the dephosphorylation of the proximal TCR signaling molecules. This results in the suppression of T cell activation and blockade of the TCR-induced stop signal. In addition to PD-1 clustering, PD-1–TCR colocalization within microclusters is required for efficient PD-1–mediated suppression. This inhibitory mechanism also functions in PD-1hi T cells generated in vivo and can be overridden by a neutralizing anti–PD-L1 antibody. Therefore, PD-1 microcluster formation is important for regulation of T cell activation.


2020 ◽  
Author(s):  
Purva Karia ◽  
Keiko Yoshioka ◽  
Wolfgang Moeder

ABSTRACTThe role of mitochondria in programmed cell death (PCD) during animal growth and development is well documented, but much less is known for plants. We previously showed that the Arabidopsis thaliana triphosphate tunnel metalloenzyme (TTM) proteins TTM1 and TTM2 are tail-anchored proteins that localize in the mitochondrial outer membrane and participate in PCD during senescence and immunity, respectively. Here, we show that TTM1 is specifically involved in senescence induced by abscisic acid (ABA). Moreover, phosphorylation of TTM1 by multiple mitogen-activated protein kinases (MAPKs) regulates its function and turnover. A combination of proteomics and in vitro kinase assays revealed three major phosphorylation sites of TTM1 (S10, S437, and S490), which are phosphorylated upon perception of senescence cues such as ABA and prolonged darkness. S437 is phosphorylated by the MAP kinases MPK3 and MPK4, and S437 phosphorylation is essential for TTM1 function in senescence. These MPKs, together with three additional MAP kinases (MPK1, MPK7, and MPK6), phosphorylate S10 and S490, marking TTM1 for protein turnover, which likely prevents uncontrolled cell death. Taken together, our results show that multiple MPKs regulate the function and turnover of the mitochondrial protein TTM1 during senescence-related PCD, revealing a novel link between mitochondria and PCD.SummaryEmail addresses: [email protected]


Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3247
Author(s):  
Lingxiao Ye ◽  
Zhengxin Zhu ◽  
Xiaochuan Chen ◽  
Haoran Zhang ◽  
Jiaqi Huang ◽  
...  

Binding of programmed cell death ligand 1 (PD-L1) to its receptor programmed cell death protein 1 (PD-1) can lead to the inactivation of cytotoxic T lymphocytes, which is one of the mechanisms for immune escape of tumors. Immunotherapy based on this mechanism has been applied in clinic with some remaining issues such as drug resistance. Exosomal PD-L1 derived from tumor cells is considered to play a key role in mediating drug resistance. Here, the effects of various tumor-derived exosomes and tumor-derived exosomal PD-L1 on tumor progression are summarized and discussed. Researchers have found that high expression of exosomal PD-L1 can inhibit T cell activation in in vitro experiments, but the function of exosomal PD-L1 in vivo remains controversial. In addition, the circulating exosomal PD-L1 has high potential to act as an indicator to evaluate the clinical effect. Moreover, therapeutic strategy targeting exosomal PD-L1 is discussed, such as inhibiting the biogenesis or secretion of exosomes. Besides, some specific methods based on the strategy of inhibiting exosomes are concluded. Further study of exosomal PD-L1 may provide an effective and safe approach for tumor treatment, and targeting exosomal PD-L1 by inhibiting exosomes may be a potential method for tumor treatment.


1998 ◽  
Vol 102 (11) ◽  
pp. 2002-2010 ◽  
Author(s):  
L Guedez ◽  
W G Stetler-Stevenson ◽  
L Wolff ◽  
J Wang ◽  
P Fukushima ◽  
...  

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