scholarly journals The transcription factor Gli3 regulates differentiation of fetal CD4–CD8– double-negative thymocytes

Blood ◽  
2005 ◽  
Vol 106 (4) ◽  
pp. 1296-1304 ◽  
Author(s):  
Ariadne L. Hager-Theodorides ◽  
Johannes T. Dessens ◽  
Susan V. Outram ◽  
Tessa Crompton
Keyword(s):  
Transcription Factor ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Differentiation ◽  
Double Negative ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Double Positive ◽  
Dose Dependent

AbstractGlioblastoma 3 (Gli3) is a transcription factor involved in patterning and oncogenesis. Here, we demonstrate a role for Gli3 in thymocyte development. Gli3 is differentially expressed in fetal CD4–CD8– double-negative (DN) thymocytes and is most highly expressed at the CD44+ CD25– DN (DN1) and CD44–CD25– (DN4) stages of development but was not detected in adult thymocytes. Analysis of null mutants showed that Gli3 is involved at the transitions from DN1 to CD44+ CD25+ DN (DN2) cell and from DN to CD4+CD8+ double-positive (DP) cell. Gli3 is required for differentiation from DN to DP thymocyte, after pre–T-cell receptor (TCR) signaling but is not necessary for pre-TCR–induced proliferation or survival. The effect of Gli3 was dose dependent, suggesting its direct involvement in the transcriptional regulation of genes controlling T-cell differentiation during fetal development.

scholarly journals Pre–T Cell Receptor (Tcr) and Tcr-Controlled Checkpoints in T Cell Differentiation Are Set by Ikaros

1999 ◽  
Vol 190 (8) ◽  
pp. 1039-1048 ◽  
Author(s):  
Susan Winandy ◽  
Li Wu ◽  
Jin-Hong Wang ◽  
Katia Georgopoulos
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Differentiation ◽  
Tcr Signaling ◽  
Double Positive ◽  
Single Positive ◽  
T Cell Malignancies ◽  
Deficient Mice

T cell differentiation relies on pre–T cell receptor (TCR) and TCR signaling events that take place at successive steps of the pathway. Here, we show that two of these T cell differentiation checkpoints are regulated by Ikaros. In the absence of Ikaros, double negative thymocytes can differentiate to the double positive stage without expression of a pre-TCR complex. Subsequent events in T cell development mediated by TCR involving transition from the double positive to the single positive stage are also regulated by Ikaros. Nonetheless, in Ikaros-deficient thymocytes, the requirement of pre-TCR expression for expansion of immature thymocytes as they progress to the double positive stage is still maintained, and the T cell malignancies that invariably arise in the thymus of Ikaros-deficient mice are dependent on either pre-TCR or TCR signaling. We conclude that Ikaros regulates T cell differentiation, selection, and homeostasis by providing signaling thresholds for pre-TCR and TCR.

scholarly journals Disregulated expression of the transcription factor ThPOK during T-cell development leads to high incidence of T-cell lymphomas

2015 ◽  
Vol 112 (25) ◽  
pp. 7773-7778 ◽  
Author(s):  
Hyung-Ok Lee ◽  
Xiao He ◽  
Jayati Mookerjee-Basu ◽  
Dai Zhongping ◽  
Xiang Hua ◽  
...  
Keyword(s):  
Transcription Factor ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
T Cell Development ◽  
Cell Receptor ◽  
Cell Development ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Double Positive ◽  
Human T Cell

The transcription factor T-helper-inducing POZ/Krueppel-like factor (ThPOK, encoded by the Zbtb7b gene) plays widespread and critical roles in T-cell development, particularly as the master regulator of CD4 commitment. Here we show that mice expressing a constitutive T-cell–specific ThPOK transgene (ThPOKconst mice) develop thymic lymphomas. These tumors resemble human T-cell acute lymphoblastic leukemia (T-ALL), in that they predominantly exhibit activating Notch1 mutations. Lymphomagenesis is prevented if thymocyte development is arrested at the DN3 stage by recombination-activating gene (RAG) deficiency, but restored by introduction of a T-cell receptor (TCR) transgene or by a single injection of anti-αβTCR antibody into ThPOKconst RAG-deficient mice, which promotes development to the CD4+8+ (DP) stage. Hence, TCR signals and/or traversal of the DN (double negative) > DP (double positive) checkpoint are required for ThPOK-mediated lymphomagenesis. These results demonstrate a novel link between ThPOK, TCR signaling, and lymphomagenesis. Finally, we present evidence that ectopic ThPOK expression gives rise to a preleukemic and self-perpetuating DN4 lymphoma precursor population. Our results collectively define a novel role for ThPOK as an oncogene and precisely map the stage in thymopoiesis susceptible to ThPOK-dependent tumor initiation.

scholarly journals Regulation of thymocyte development through CD3. II. Expression of T cell receptor beta CD3 epsilon and maturation to the CD4+8+ stage are highly correlated in individual thymocytes.

1993 ◽  
Vol 178 (6) ◽  
pp. 1867-1875 ◽  
Author(s):  
C N Levelt ◽  
R Carsetti ◽  
K Eichmann
Keyword(s):  
Signal Transduction ◽  
T Cell ◽  
T Cell Receptor ◽  
Alternative Hypothesis ◽  
Cell Receptor ◽  
Surface Expression ◽  
Beta Chain ◽  
Thymocyte Development ◽  
Double Positive ◽  
Highly Correlated

Recent studies have shown that maturation of CD4-8- double negative (DN) thymocytes to the CD4+8+ double positive (DP) stage is dependent on expression of the T cell receptor (TCR)-beta polypeptide. The exact mechanism by which the TCR-beta chain regulates this maturation step remains unknown. Previous experiments had suggested that in the presence of some TCR+ thymocytes, additional DN thymocytes not expressing a TCR-beta chain may be recruited to mature to the DP stage. The recent demonstration of an immature TCR-beta-CD3 complex on early thymocytes lead to the alternative hypothesis that signal transduction through an immature TCR-CD3 complex may induce maturation to the DP stage. In the latter case, maturation to the DP stage would depend on the expression of TCR-beta-CD3 in the same cell. We examined these two hypotheses by studying the expression of the intra- and extracellular CD3 epsilon, CD3 zeta, and TCR-beta polypeptides in intrathymic subpopulations during embryogenesis. CD3 epsilon and CD3 zeta were expressed intracellularly 2 and 1 d, respectively, before intracellular expression of the TCR-beta chain, potentially allowing immediate surface expression of an immature TCR-beta-CD3 complex as soon as functional rearrangement of a TCR-beta gene locus has been accomplished. Calcium mobilization could be induced by stimulation with anti-CD3 epsilon mAb as soon as intracellular TCR-beta was detectable, suggesting that a functional TCR-beta-CD3 complex is indeed expressed on the surface of early thymocytes. From day 17 on, most cells were in the DP stage, and over 95% of the DP cells expressed on the TCR-beta chain intracellularly. At day 19 of gestation, extremely low concentrations of TCR-beta chain and CD3 epsilon were detectable on the cell surface of nearly all thymocytes previously thought to be TCR-CD3 negative. These findings strongly support the hypothesis that maturation to the DP stage depends on surface expression of and subsequent signal transduction through an immature TCR-beta-CD3 complex and suggest that maturation to the DP stage by recruitment, if it occurs at all, is of minor relevance.

scholarly journals Restricting Zap70 Expression to CD4+CD8+ Thymocytes Reveals a T Cell Receptor–dependent Proofreading Mechanism Controlling the Completion of Positive Selection

2003 ◽  
Vol 197 (3) ◽  
pp. 363-373 ◽  
Author(s):  
Xiaolong Liu ◽  
Anthony Adams ◽  
Kathryn F. Wildt ◽  
Bruce Aronow ◽  
Lionel Feigenbaum ◽  
...  
Keyword(s):  
T Cell ◽  
Positive Selection ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Novel Approach ◽  
Single Positive ◽  
Tcr Signals

Although T cell receptor (TCR) signals are essential for intrathymic T cell–positive selection, it remains controversial whether they only serve to initiate this process, or whether they are required throughout to promote thymocyte differentiation and survival. To address this issue, we have devised a novel approach to interfere with thymocyte TCR signaling in a developmental stage-specific manner in vivo. We have reconstituted mice deficient for Zap70, a tyrosine kinase required for TCR signaling and normally expressed throughout T cell development, with a Zap70 transgene driven by the adenosine deaminase (ADA) gene enhancer, which is active in CD4+CD8+ thymocytes but inactive in CD4+ or CD8+ single-positive (SP) thymocytes. In such mice, termination of Zap70 expression impaired TCR signal transduction and arrested thymocyte development after the initiation, but before the completion, of positive selection. Arrested thymocytes had terminated Rag gene expression and up-regulated TCR and Bcl-2 expression, but failed to differentiate into mature CD4 or CD8 SP thymocytes, to be rescued from death by neglect or to sustain interleukin 7Rα expression. These observations identify a TCR-dependent proofreading mechanism that verifies thymocyte TCR specificity and differentiation choices before the completion of positive selection.

scholarly journals Indian hedgehog (Ihh) both promotes and restricts thymocyte differentiation

Blood ◽  
2009 ◽  
Vol 113 (10) ◽  
pp. 2217-2228 ◽  
Author(s):  
Susan V. Outram ◽  
Ariadne L. Hager-Theodorides ◽  
Divya K. Shah ◽  
Nicola J. Rowbotham ◽  
Ekati Drakopoulou ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Development ◽  
Cell Development ◽  
Conditional Knockout ◽  
Indian Hedgehog ◽  
Double Negative ◽  
Wild Type ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Double Positive

Abstract We show that Indian Hedgehog (Ihh) regulates T-cell development and homeostasis in both fetal and adult thymus, controlling thymocyte number. Fetal Ihh−/− thymi had reduced differentiation to double-positive (DP) cell and reduced cell numbers compared with wild-type littermates. Surprisingly, fetal Ihh+/− thymi had increased thymocyte numbers and proportion of DP cells relative to wild type, indicating that Ihh also negatively regulates thymocyte development. In vitro treatment of thymus explants with exogenous recombinant Hedgehog protein promoted thymocyte development in Ihh−/− thymi but inhibited thymocyte development in Ihh+/−, confirming both positive and negative regulatory functions of Ihh. Analysis of Rag−/−Ihh+/− thymi showed that Ihh promotes T-cell development before pre–T-cell receptor (pre-TCR) signaling, but negatively regulates T-cell development only after pre-TCR signaling has taken place. We show that Ihh is most highly expressed by the DP population and that Ihh produced by DP cells feeds back to negatively regulate the differentiation and proliferation of their double-negative progenitors. Thus, differentiation from double-negative to DP cell, and hence the size of the DP population, is dependent on the concentration of Ihh in the thymus. Analysis of Ihh conditional knockout and heterozygote adult mice showed that Ihh also influences thymocyte number in the adult.

scholarly journals Conditional Knockout Mice Reveal an Essential Role of Protein Phosphatase 4 in Thymocyte Development and Pre-T-Cell Receptor Signaling

2006 ◽  
Vol 27 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Jr-Wen Shui ◽  
Mickey C.-T. Hu ◽  
Tse-Hua Tan
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Cell Receptor ◽  
Conditional Knockout ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Deficient Mice

ABSTRACT Okadaic acid-sensitive serine/threonine phosphatases have been shown to regulate interleukin-2 transcription and T-cell activation. Okadaic acid inhibits protein phosphatase 4 (PP4), a novel PP2A-related serine/threonine phosphatase, at a 50% inhibitory concentration (IC50) comparable to that for PP2A. This raises the possibility that some cellular functions of PP2A, determined in T cells by using okadaic acid, may in fact be those of PP4. To investigate the in vivo roles of PP4 in T cells, we generated conventional and T-cell-specific PP4 conditional knockout mice. We found that the ablation of PP4 led to the embryonic lethality of mice. PP4 gene deletion in the T-cell lineage resulted in aberrant thymocyte development, including T-cell arrest at the double-negative 3 stage (CD4− CD8− CD25+ CD44−), abnormal thymocyte maturation, and lower efficacy of positive selection. PP4-deficient thymocytes showed decreased proliferation and enhanced apoptosis in vivo. Analysis of pre-T-cell receptor (pre-TCR) signaling further revealed impaired calcium flux and phospholipase C-γ1-extracellular signal-regulated kinase activation in the absence of PP4. Anti-CD3 injection in PP4-deficient mice led to enhanced thymocyte apoptosis, accompanied by increased proapoptotic Bim but decreased antiapoptotic Bcl-xL protein levels. In the periphery, antigen-specific T-cell proliferation and T-cell-mediated immune responses in PP4-deficient mice were dramatically compromised. Thus, our results indicate that PP4 is essential for thymocyte development and pre-TCR signaling.

scholarly journals Analysis of Thymocyte Development Reveals That the Gtpase Rhoa Is a Positive Regulator of T Cell Receptor Responses in Vivo

2001 ◽  
Vol 194 (7) ◽  
pp. 903-914 ◽  
Author(s):  
Isabelle Corre ◽  
Manuel Gomez ◽  
Susina Vielkind ◽  
Doreen A. Cantrell
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Development ◽  
Cell Receptor ◽  
Cell Development ◽  
T Cell Differentiation ◽  
Thymocyte Development

Loss of function of the guanine nucleotide binding protein RhoA blocks pre-T cell differentiation and survival indicating that this GTPase is a critical signaling molecule during early thymocyte development. Previous work has shown that the Rho family GTPase Rac-1 can initiate changes in actin dynamics necessary and sufficient for pre-T cell development. The present data now show that Rac-1 actions in pre-T cells require Rho function but that RhoA cannot substitute for Rac-1 and induce the actin cytoskeletal changes necessary for pre-T cell development. Activation of Rho is thus not sufficient to induce pre-T cell differentiation or survival in the absence of the pre-T cell receptor (TCR). The failure of RhoA activation to impact on pre-TCR–mediated signaling was in marked contrast to its actions on T cell responses mediated by the mature TCR α/β complex. Cells expressing active RhoA were thus hyperresponsive in the context of TCR-induced proliferation in vitro and in vivo showed augmented positive selection of thymocytes expressing defined TCR complexes. This reveals that RhoA function is not only important for pre-T cells but also plays a role in determining the fate of mature T cells.

scholarly journals Requirement of CD3 Complex–associated Signaling Functions for Expression of Rearranged T Cell Receptor β VDJ Genes in Early Thymic Development

1998 ◽  
Vol 188 (9) ◽  
pp. 1669-1678 ◽  
Author(s):  
Andreas Würch ◽  
Judit Biro ◽  
Alexandre J. Potocnik ◽  
Ingrid Falk ◽  
Horst Mossmann ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Thymocyte Development ◽  
Double Positive ◽  
Thymic Development ◽  
Cell Progression ◽  
Complex Signaling ◽  
Polypeptide Chains

During αβ thymocyte development, the clonotypic αβ–T cell receptor (TCR) is preceded by sequentially expressed immature versions of the TCR–CD3 complex: the pre-TCR, containing a clonotypic TCR-β chain and invariant pre-Tα, is expressed on pre-T cells before rearrangement of the TCR-α locus. Moreover, clonotype-independent CD3 complexes (CIC) appear on pro-T cells before VDJ rearrangements of TCR-β genes. The pre-TCR is known to mediate TCR-β selection, the prerequisite for maturation of CD4−8− double negative (DN) thymocytes to the CD4+8+ double positive stage. A developmental function of CIC has so far not been delineated. In mice single deficient and double deficient for CD3ζ/η and/or p56lck, we observe a pronounced reduction in the proportions of CD25+ DN thymocytes that express intracellular TCR-β chains. TCR-β transcripts are reduced in parallel with TCR-β polypeptide chains whereas no reduction in TCR-β locus rearrangements could be detected. Wild-type levels of TCR-β transcripts and of cells expressing TCR-β polypeptide chains are induced by treatment with anti-CD3ε mAb. The data suggest that the initial expression of rearranged TCR-β VDJ genes in pro-T cell to pre-T cell progression is dependent on CD3 complex signaling, and thus define a putative developmental function for CIC.

scholarly journals Lck Domains Differentially Contribute to Pre–T Cell Receptor (Tcr)–And TCR-α/β–Regulated Developmental Transitions

2000 ◽  
Vol 191 (4) ◽  
pp. 703-716 ◽  
Author(s):  
Kui Lin ◽  
Nancy S. Longo ◽  
Xin Wang ◽  
Judy A. Hewitt ◽  
Kristin M. Abraham
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Protein Tyrosine Kinase ◽  
Catalytic Domain ◽  
Cell Receptor ◽  
Double Negative ◽  
Double Positive ◽  
Developmental Transitions ◽  
Major Transitions ◽  
Single Positive

Maturational changes at the CD4−CD8− double negative (DN) to CD4+CD8+ double positive (DP) transition are dependent on signals generated via the pre–T cell receptor (TCR) and the nonreceptor protein tyrosine kinase p56lck (Lck). How Lck activities are stimulated or relayed after pre-TCR formation remains obscure. Our structure–function mapping of Lck thymopoietic properties reveals that the noncatalytic domains of Lck are specialized to signal efficient cellular expansion at DN to DP transition. Moreover, although substitution of the Lck catalytic domain with FynT sequences minimally impacts DP development, single positive thymocytes are most efficiently produced in the presence of kinases containing both the NH2-terminal and catalytic regions of Lck. These findings demonstrate that the Lck structure is uniquely adapted to mediate signals at both major transitions in thymopoiesis.

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