scholarly journals A role for phagocytosis in inducing cell death during thymocyte negative selection

2019 ◽  
Author(s):  
Nadia S. Kurd ◽  
Lydia K. Lutes ◽  
Jaewon Yoon ◽  
Ivan L. Dzhagalov ◽  
Ashley Hoover ◽  
...  
Keyword(s):  
Cell Death ◽  
Negative Selection ◽  
Death Process ◽  
Tcr Signaling ◽  
Step Model ◽  
Self Tolerance ◽  
Timely Death ◽  
Self Peptides

AbstractAutoreactive thymocytes are eliminated during negative selection in the thymus, a process important for establishing self-tolerance. Thymic phagocytes serve to remove dead thymocytes, but whether they play additional roles during negative selection remains unclear. Here, we demonstrate that phagocytosis promotes negative selection, and that negative selection is more efficient when the phagocyte also presents the negative selecting peptide. Our findings support a two-step model for negative selection in which thymocytes initiate the death process following strong TCR signaling, but ultimately depend upon phagocytosis for their timely death. Thus, the phagocytic capability of cells that present self-peptides is a key determinant of thymocyte fate.

scholarly journals A role for phagocytosis in inducing cell death during thymocyte negative selection

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Nadia S Kurd ◽  
Lydia K Lutes ◽  
Jaewon Yoon ◽  
Shiao Wei Chan ◽  
Ivan L Dzhagalov ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Cd8 T Cells ◽  
Negative Selection ◽  
Death Process ◽  
Tcr Signaling ◽  
Self Tolerance ◽  
Self Peptides

Autoreactive thymocytes are eliminated during negative selection in the thymus, a process important for establishing self-tolerance. Thymic phagocytes serve to remove dead thymocytes, but whether they play additional roles during negative selection remains unclear. Here, using a murine thymic slice model in which thymocytes undergo negative selection in situ, we demonstrate that phagocytosis promotes negative selection, and provide evidence for the escape of autoreactive CD8 T cells to the periphery when phagocytosis in the thymus is impaired. We also show that negative selection is more efficient when the phagocyte also presents the negative selecting peptide. Our findings support a model for negative selection in which the death process initiated following strong TCR signaling is facilitated by phagocytosis. Thus, the phagocytic capability of cells that present self-peptides is a key determinant of thymocyte fate.

scholarly journals Transforming Growth Factor-beta signaling in αβ thymocytes promotes negative selection

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mark J. McCarron ◽  
Magali Irla ◽  
Arnauld Sergé ◽  
Saidi M’Homa Soudja ◽  
Julien C. Marie
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Negative Selection ◽  
Transforming Growth Factor ◽  
Selection Process ◽  
Multiple Organ ◽  
Cytokine Signaling ◽  
Tcr Signaling ◽  
Self Tolerance ◽  
Growth Factor Beta

AbstractIn the thymus, the T lymphocyte repertoire is purged of a substantial portion of highly self-reactive cells. This negative selection process relies on the strength of TCR-signaling in response to self-peptide-MHC complexes, both in the cortex and medulla regions. However, whether cytokine-signaling contributes to negative selection remains unclear. Here, we report that, in the absence of Transforming Growth Factor beta (TGF-β) signaling in thymocytes, negative selection is significantly impaired. Highly autoreactive thymocytes first escape cortical negative selection and acquire a Th1-like-phenotype. They express high levels of CXCR3, aberrantly accumulate at the cortico-medullary junction and subsequently fail to sustain AIRE expression in the medulla, escaping medullary negative selection. Highly autoreactive thymocytes undergo an atypical maturation program, substantially accumulate in the periphery and induce multiple organ-autoimmune-lesions. Thus, these findings reveal TGF-β in thymocytes as crucial for negative selection with implications for understanding T cell self-tolerance mechanisms.

scholarly journals Dormant pathogenic CD4+ T cells are prevalent in the peripheral repertoire of healthy mice

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna Cebula ◽  
Michal Kuczma ◽  
Edyta Szurek ◽  
Maciej Pietrzak ◽  
Natasha Savage ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell Receptors ◽  
Negative Selection ◽  
Regulatory Cells ◽  
Central Tolerance ◽  
Therapeutic Advantage ◽  
Autoreactive T Cell ◽  
Peptide Complexes ◽  
Self Peptides

Abstract Thymic central tolerance eliminates most immature T cells with autoreactive T cell receptors (TCR) that recognize self MHC/peptide complexes. Regardless, an unknown number of autoreactive CD4+Foxp3− T cells escape negative selection and in the periphery require continuous suppression by CD4+Foxp3+ regulatory cells (Tregs). Here, we compare immune repertoires of Treg-deficient and Treg-sufficient mice to find Tregs continuously constraining one-third of mature CD4+Foxp3− cells from converting to pathogenic effectors in healthy mice. These dormant pathogenic clones frequently express TCRs activatable by ubiquitous autoantigens presented by class II MHCs on conventional dendritic cells, including self-peptides that select them in the thymus. Our data thus suggest that identification of most potentially autoreactive CD4+ T cells in the peripheral repertoire is critical to harness or redirect these cells for therapeutic advantage.

scholarly journals Regulation of proximal T cell receptor signaling and tolerance induction by deubiquitinase Usp9X

2014 ◽  
Vol 211 (10) ◽  
pp. 1947-1955 ◽  
Author(s):  
Edwina Naik ◽  
Joshua D. Webster ◽  
Jason DeVoss ◽  
Jinfeng Liu ◽  
Rowena Suriben ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tolerance Induction ◽  
Ubiquitin Ligases ◽  
Cell Receptor ◽  
Lymphoproliferative Disease ◽  
Deubiquitinating Enzymes ◽  
Tcr Signaling ◽  
Self Tolerance ◽  
A Cell

The T cell hyperproliferation and autoimmune phenotypes that manifest in mice lacking E3 ubiquitin ligases such as Cbl, ITCH, or GRAIL highlight the importance of ubiquitination for the maintenance of peripheral T cell tolerance. Less is known, however, about the deubiquitinating enzymes that regulate T cell proliferation and effector function. Here, we define a cell intrinsic role for the deubiquitinase Usp9X during proximal TCR signaling. Usp9X-deficient T cells were hypoproliferative, yet mice with T cell–specific Usp9x deletion had elevated numbers of antigen-experienced T cells and expanded PD-1 and OX40-expressing populations consistent with immune hyperactivity. Aged Usp9x KO mice developed lupus-like autoimmunity and lymphoproliferative disease, indicating that ubiquitin ligases and deubiquitinases maintain the delicate balance between effective immunity and self-tolerance.

scholarly journals Correction: PML induces a novel caspase-independent cell death process

10.1038/8706 ◽  
1999 ◽  
Vol 22 (1) ◽  
pp. 115-115 ◽  
Author(s):  
Fredérique Quignon
Keyword(s):  
Cell Death ◽  
Death Process ◽  
Cell Death Process

scholarly journals Analysis of programmed cell death in mouse fetal oocytes

Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 241-252 ◽  
Author(s):  
A M Lobascio ◽  
F G Klinger ◽  
M L Scaldaferri ◽  
D Farini ◽  
M De Felici
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Death Process ◽  
Parp Cleavage ◽  
Tunel Staining ◽  
Calpain Inhibitor ◽  
Dna Ladder ◽  
Caspase 2

We report a short-term culture system that allowsto define novel characteristic of programmed cell death (PCD) in fetal oocytes and to underscore newaspects of this process. Mouse fetal oocytes culturedin conditions allowingmeiotic prophase I progression underwent apoptotic degeneration waves as revealed by TUNEL staining. TEM observations revealed recurrent atypical apoptotic morphologies characterized by the absence of chromatin margination and nuclear fragmentation; oocytes with autophagic and necrotic features were also observed. Further characterization of oocyte death evidenced DNA ladder, Annexin V binding, PARP cleavage, and usually caspase activation (namely caspase-2). In the aim to modulate the oocyte death process, we found that the addition to the culture medium of the pancaspase inhibitors Z-VAD orcaspase-2-specific inhibitor Z-VDVAD resulted in a partial and transient prevention of this process. Oocyte death was significantly reduced by the antioxidant agent NAC and partly prevented by KL and IGF-I growth factors. Finally, oocyte apoptosis was reduced by calpain inhibitor I and increased by rapamycin after prolonged culture.These results support the notion that fetal oocytes undergo degeneration mostly by apoptosis. This process is, however, often morphologically atypical and encompasses other forms of cell death including caspase-independent apoptosis and autophagia. The observation that oocyte death occurs mainly at certain stages of meiosis and can only be attenuated by typical anti-apoptotic treatments favors the notion that it is controlled at least in part by stage-specific oocyte-autonomous meiotic checkpoints and when activated is little amenable to inhibition being the oocyte able to switch back and forth among different death pathways.

scholarly journals Correction: IL-4 Regulates Bim Expression and Promotes B Cell Maturation in Synergy with BAFF Conferring Resistance to Cell Death at Negative Selection Checkpoints

2018 ◽  
Vol 201 (8) ◽  
pp. 2520-2520
Author(s):  
Alessandra Granato ◽  
Elize A. Hayashi ◽  
Barbara J. A. Baptista ◽  
Maria Bellio ◽  
Alberto Nobrega
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Negative Selection ◽  
Cell Maturation ◽  
B Cell Maturation

scholarly journals Production of Prodiginines Is Part of a Programmed Cell Death Process in Streptomyces coelicolor

2018 ◽  
Vol 9 ◽  
Author(s):  
Elodie Tenconi ◽  
Matthew F. Traxler ◽  
Charline Hoebreck ◽  
Gilles P. van Wezel ◽  
Sébastien Rigali
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Streptomyces Coelicolor ◽  
Death Process ◽  
Cell Death Process

Characterization of cell death process in plant cells induced by hipoxia and anoxia

2000 ◽  
Vol 28 (5) ◽  
pp. A372-A372
Author(s):  
E. N. Baranova ◽  
N. V. Kononenko ◽  
T. V. Bragina ◽  
G. M. Grineva ◽  
T. P. Astafurova ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Cells ◽  
Death Process ◽  
Cell Death Process
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