Aberrant T cell differentiation in the absence of Dicer

Dicer is an RNaseIII-like enzyme that is required for generating short interfering RNAs and microRNAs. The latter have been implicated in regulating cell fate determination in invertebrates and vertebrates. To test the requirement for Dicer in cell-lineage decisions in a mammalian organism, we have generated a conditional allele of dicer-1 (dcr-1) in the mouse. Specific deletion of dcr-1 in the T cell lineage resulted in impaired T cell development and aberrant T helper cell differentiation and cytokine production. A severe block in peripheral CD8+ T cell development was observed upon dcr-1 deletion in the thymus. However, Dicer-deficient CD4+ T cells, although reduced in numbers, were viable and could be analyzed further. These cells were defective in microRNA processing, and upon stimulation they proliferated poorly and underwent increased apoptosis. Independent of their proliferation defect, Dicer-deficient helper T cells preferentially expressed interferon-γ, the hallmark effector cytokine of the Th1 lineage.

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Notch Activation Converts B Cells into a T Cell Fate at the Earliest Stages of B Cell Committed Progenitors.

Blood ◽

10.1182/blood.v106.11.3151.3151 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3151-3151

Author(s):

Jalal Taneera ◽

Emma Smith ◽

Mikael Sigvardsson ◽

Emil Hansson ◽

Urban Lindahl ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cell Fate ◽

T Cell Development ◽

Cell Development ◽

Cell Stage ◽

Cell Commitment ◽

Notch Activation

Abstract Notch activation has been suggested to promote T cell development at the expense of B cell commitment at the level of a common lymphoid progenitor prior to B cell commitment. Here, we explored the possibility that Notch activation might be able to switch the fate of already committed B cell progenitors towards T cell development upon Notch activation. To address this we overexpressed constitutively activated Notch-3 (N3IC) in B cell progenitors purified from transgenic mice in which human CD25 is expressed under control of the λ5 promoter. Strikingly, whereas untransduced and control transduced B220+λ5+CD3− B cell progenitors gave rise exclusively to B cells, CD4+ and CD8+ T cells but no B cells were derived from N3IC-transduced cells when transplanted into sublethally irradiated NOD-SCID mice. Gene expression profiling demonstrated that untransduced B220+ λ5+CD3− B cell progenitors expressed λ5 and CD19 but not the T cell specific genes GATA-3, lck and pTα, whereas CD3+ T cells derived from N3IC-transduced B220+λ5+CD3−cells failed to express λ5 and CD19, but were positive for GATA-3, lck and pTα expression as well as a and b T cell rearrangement. Furthermore, DJ rearrangements were detected at very low levels in CD3+ cells isolated from normal non-transduced BM, but were more abundant in the N3IC-transduced CD3+ BM cells. Noteworthy, N3IC-transduced B220+λ5+CD3−CD19+ proB cell progenitors failed to generate B as well as T cells, whereas N3IC-transduced B220+λ5+CD3−CD19− pre-proB cells produced exclusively T cells, even when evaluated at low cell numbers. In conclusion Notch activation can switch committed B cell progenitors from a B cell to a T cell fate, but this plasticity is lost at the Pro-B cell stage, upon upregulation of CD19 expression.

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Towards Understanding & Uncovering New Key Players in T-Cell Development upon Aging

Blood ◽

10.1182/blood-2019-127294 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2482-2482

Author(s):

Hanane Boukarabila ◽

Kalpana Nattamai ◽

Medhanie Assmelash Mulaw ◽

Hartmut Geiger

Keyword(s):

T Cells ◽

T Cell ◽

Differentially Expressed Genes ◽

T Cell Development ◽

Cell Lineage ◽

Cell Development ◽

Differentially Expressed ◽

Rna Seq ◽

Thymic Involution ◽

Total P

Aging-associated immune remodeling (AAIR) leads to an impaired ability to respond to vaccination and combat infections, and is due to many factors acting in concert. Several studies have linked the T-cell decline that occurs with age to thymic involution. However, there is novel and mounting evidence that also aged lymphoid-primed multipotent progenitors (LMPPs) are immune system intrinsic players in AAIR. However, very little is known on molecular and cellular mechanisms by which aging LMPPs could drive this AAIR phenomenon. Deciphering the underlying mechanisms is of crucial importance for developing new therapies to attenuate AAIR. Here, we present new data demonstrating the dysregulated pathways associated with aged LMPPs and the cellular changes in early thymic differentiation events in driving AAIR. To assess the T-lineage potential of aged LMPPs, we performed single cells ex-vivo OP9D assays using LMPPs (Lin-cKit+Sca1+CD34-Flt3hi) from aged (18-20 month-old) and young (8-10 week-old) C57BL/6 animals as controls. The frequencies of T-cell lineage potential in aged LMPPs and young LMPPs at the single cell level were very similar. This result was also validated in vivo by transplantation assays where 5000 aged or young LMPPs were injected into sub-lethally irradiated young recipients followed by T-cell lineage (CD4+ & CD8+) analysis in the peripheral blood (PB) at 4 weeks post transplantation (Mean; Y:12,75 vs A:16:23 % of total, p=0.46). However, aged LMPPs were associated with a dramatic disadvantage of PB T-cells at 4 weeks post injections (Mean; Y:9 vs A:2.3 % of total, p<0.0001) and in the development of all thymic stages of thymocytes, from early double negative stage CD4-CD8-(DN1) (Mean; Y:30 vs A:8 % of parent, p<0.0001) to double positive stage CD4+CD8+(DP) (Mean; Y:53 vs A:15 % of parent, p<0.0001), as well as single positive (SP) CD4+(Mean; Y:54 vs A:13 % of parent, p<0.0001) and CD8+(Mean; Y:45 vs A:10 % of parent, p<0.0001) thymocytes when intravenously transplanted in combination with 1:1 ratio of young LMPPs into young recipients. To overcome a potential homing to the thymus bias of aged LMPPs in competitive transplants, we performed intra-thymic injections of young and aged LMPPs with identical ratios into sub-lethally irradiated young recipients. The analysis of PB at 4 weeks post injections show a dramatic reduction of PB T-cells derived from aged LMPPs in comparison with young LMPPs (Mean; Y:14.8 vs A:8 % of total, p<0.0001). There was primarily a strong disadvantage towards generating DP stage (Mean; Y:46 vs A:28 % of parent, p<0.0001), suggesting that the intra-thymic injections indeed alleviated the dramatic decrease in the early thymocyte stage DN1 (Mean; Y:31 vs A:22 % of parent, p<0.05). This suggests that aged LMPPs confer a T-cell differentiation and maybe an additional homing to the thymus defect. We also performed RNA-Seq analyses on LMPPs from young and aged mice. Unsupervised hierarchical clustering of differentially expressed genes between young and aged LMPPs highlighted a clear dysregulation of only a few pathways that are involved in T-cell development such as Notch signaling. We next correlated our RNA-Seq data with other immunological signatures in attempt to look for more T-cell specific key factors that are differentially expressed between young and aged LMPPs. Importantly, the results show that the data from our RNA-Seq correlated with more than 400 immunological signatures among which 25 were most highly correlated. Interestingly, this correlation has allowed us to curate a list of the top 30 differentially expressed genes between young and aged LMPPs including T-cell specific transcription factors such as Satb1 and Foxo1. Altogether, our findings reveal that the T-cell immune decline that occurs with age is already imprinted in LMPPs within the bone marrow and translates into a dysregulation of signaling pathways that are directly related to T-cell development. Targeting these pathways could open up new perspectives in attenuating AAIR. Disclosures No relevant conflicts of interest to declare.

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B cell adaptor for PI3-kinase (BCAP) modulates CD8+ effector and memory T cell differentiation

Journal of Experimental Medicine ◽

10.1084/jem.20171820 ◽

2018 ◽

Vol 215 (9) ◽

pp. 2429-2443 ◽

Cited By ~ 10

Author(s):

Mark D. Singh ◽

Minjian Ni ◽

Jenna M. Sullivan ◽

Jessica A. Hamerman ◽

Daniel J. Campbell

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

B Cell ◽

Cd8 T Cells ◽

T Cell Development ◽

Cell Development ◽

T Cell Differentiation ◽

Pi3k Signaling ◽

Memory T Cell

CD8+ T cells respond to signals via the T cell receptor (TCR), costimulatory molecules, and immunoregulatory cytokines by developing into diverse populations of effector and memory cells. The relative strength of phosphoinositide 3-kinase (PI3K) signaling early in the T cell response can dramatically influence downstream effector and memory T cell differentiation. We show that initial PI3K signaling during T cell activation results in up-regulation of the signaling scaffold B cell adaptor for PI3K (BCAP), which further potentiates PI3K signaling and promotes the accumulation of CD8+ T cells with a terminally differentiated effector phenotype. Accordingly, BCAP-deficient CD8+ T cells have attenuated clonal expansion and altered effector and memory T cell development following infection with Listeria monocytogenes. Thus, induction of BCAP serves as a positive feedback circuit to enhance PI3K signaling in activated CD8+ T cells, thereby acting as a molecular checkpoint regulating effector and memory T cell development.

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Functional definition of a transcription factor hierarchy regulating T cell lineage commitment

Science Advances ◽

10.1126/sciadv.aaw7313 ◽

2020 ◽

Vol 6 (31) ◽

pp. eaaw7313 ◽

Cited By ~ 3

Author(s):

Laura Garcia-Perez ◽

Farbod Famili ◽

Martijn Cordes ◽

Martijn Brugman ◽

Marja van Eggermond ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Transcription Factor ◽

T Cell ◽

Notch Signaling ◽

Target Genes ◽

T Cell Development ◽

Cell Lineage ◽

Specific Protein ◽

Cell Development

T cell factor 1 (Tcf1) is the first T cell–specific protein induced by Notch signaling in the thymus, leading to the activation of two major target genes, Gata3 and Bcl11b. Tcf1 deficiency results in partial arrests in T cell development, high apoptosis, and increased development of B and myeloid cells. Phenotypically, seemingly fully T cell–committed thymocytes with Tcf1 deficiency have promiscuous gene expression and an altered epigenetic profile and can dedifferentiate into more immature thymocytes and non-T cells. Restoring Bcl11b expression in Tcf1-deficient cells rescues T cell development but does not strongly suppress the development of non-T cells; in contrast, expressing Gata3 suppresses their development but does not rescue T cell development. Thus, T cell development is controlled by a minimal transcription factor network involving Notch signaling, Tcf1, and the subsequent division of labor between Bcl11b and Gata3, thereby ensuring a properly regulated T cell gene expression program.

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The Route of Early T Cell Development: Crosstalk between Epigenetic and Transcription Factors

Cells ◽

10.3390/cells10051074 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1074

Author(s):

Veronica Della Chiara ◽

Lucia Daxinger ◽

Frank J. T. Staal

Keyword(s):

T Cells ◽

Transcription Factors ◽

T Cell ◽

Regulatory Networks ◽

Developmental Stages ◽

T Cell Development ◽

Cell Lineage ◽

Cell Development ◽

Multipotent Progenitors ◽

Epigenetic Regulators

Hematopoietic multipotent progenitors seed the thymus and then follow consecutive developmental stages until the formation of mature T cells. During this process, phenotypic changes of T cells entail stage-specific transcriptional programs that underlie the dynamic progression towards mature lymphocytes. Lineage-specific transcription factors are key drivers of T cell specification and act in conjunction with epigenetic regulators that have also been elucidated as crucial players in the establishment of regulatory networks necessary for proper T cell development. In this review, we summarize the activity of transcription factors and epigenetic regulators that together orchestrate the intricacies of early T cell development with a focus on regulation of T cell lineage commitment.

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An enriched network motif family regulates multistep cell fate transitions with restricted reversibility

10.1101/453522 ◽

2018 ◽

Author(s):

Yujie Ye ◽

Jordan Bailey ◽

Chunhe Li ◽

Tian Hong

Keyword(s):

Transcription Factors ◽

T Cell ◽

Cell Fate ◽

Biological Systems ◽

T Cell Development ◽

Cell Lineage ◽

Design Principles ◽

Cell Development ◽

Gene Circuit ◽

Gene Regulatory

AbstractMultistep cell fate transitions with stepwise changes of transcriptional profiles are common to many developmental, regenerative and pathological processes. The multiple intermediate cell lineage states can serve as differentiation checkpoints or branching points for channeling cells to more than one lineages. However, mechanisms underlying these transitions remain elusive. Here, we explored gene regulatory circuits that can generate multiple intermediate cellular states with stepwise modulations of transcription factors. With unbiased searching in the network topology space, we found a motif family containing a large set of networks can give rise to four attractors with the stepwise regulations of transcription factors, which limit the reversibility of three consecutive steps of the lineage transition. We found that there is an enrichment of these motifs in a transcriptional network controlling the early T cell development, and a mathematical model based on this network recapitulates multistep transitions in the early T cell lineage commitment. By calculating the energy landscape and minimum action paths for the T cell model, we quantified the stochastic dynamics of the critical factors in response to the differentiation signal with fluctuations. These results are in good agreement with experimental observations and they suggest the stable characteristics of the intermediate states in the T cell differentiation. These dynamical features may help to direct the cells to correct lineages during development. Our findings provide general design principles for multistep cell linage transitions and new insights into the early T cell development. The network motifs containing a large family of topologies can be useful for analyzing diverse biological systems with multistep transitions.Author summaryThe functions of cells are dynamically controlled in many biological processes including development, regeneration and disease progression. Cell fate transition, or the switch of cellular functions, often involves multiple steps. The intermediate stages of the transition provide the biological systems with the opportunities to regulate the transitions in a precise manner. These transitions are controlled by key regulatory genes of which the expression shows stepwise patterns, but how the interactions of these genes can determine the multistep processes were unclear. Here, we present a comprehensive analysis on the design principles of gene circuits that govern multistep cell fate transition. We found a large network family with common structural features that can generate systems with the ability to control three consecutive steps of the transition. We found that this type of networks is enriched in a gene circuit controlling the development of T lymphocyte, a crucial type of immune cells. We performed mathematical modeling using this gene circuit and we recapitulated the stepwise and irreversible loss of stem cell properties of the developing T lymphocytes. Our findings can be useful to analyze a wide range of gene regulatory networks controlling multistep cell fate transitions.

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Id proteins suppress E2A-driven innate-like T cell development prior to TCR selection

10.1101/208728 ◽

2017 ◽

Author(s):

Sumedha Roy ◽

Amanda J. Moore ◽

Cassandra Love ◽

Anupama Reddy ◽

Deepthi Rajagopalan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Large Population ◽

T Cell Development ◽

Cell Lineage ◽

Cell Development ◽

Inkt Cells ◽

Tcr Signaling ◽

Γδt Cells ◽

Id Proteins

AbstractId proteins have been shown to promote the differentiation of conventional αβ and γδT cells, and to suppress the expansion of invariant Natural Killer T (iNKT) cells and innate-like γδNKT within their respective cell lineages. However, it remains to be determined whether Id proteins regulate lineage specification in developing T cells that give rise to these distinct cell fates. Here we report that in the absence of Id2 and Id3 proteins, E2A prematurely activates genes critical for the iNKT cell lineage prior to TCR expression. Enhanced iNKT development in Id3-deficient mice lacking γδ NKT cells suggests that Id3 regulates the lineage competition between these populations. RNA-Seq analysis establishes E2A as the transcriptional regulator of both iNKT and γδNKT development. In the absence of pre-TCR signaling, Id2/Id3 deletion gives rise to a large population of iNKT cells and a unique innate-like DP population, despite the block in conventional αβ T cell development. The transcriptional profile of these unique DP cells reflects enrichment of innate-like signature genes, including PLZF (Zbtb16) and Granzyme A (Gzma). Results from these genetic models and genome-wide analyses suggest that Id proteins suppress E2A-driven innate-like T cell programs prior to TCR selection to enforce predominance of conventional T cells.

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MTOR Signaling and Metabolism in Early T Cell Development

Genes ◽

10.3390/genes12050728 ◽

2021 ◽

Vol 12 (5) ◽

pp. 728

Author(s):

Guy Werlen ◽

Ritika Jain ◽

Estela Jacinto

Keyword(s):

T Cells ◽

T Cell ◽

Cell Fate ◽

T Cell Activation ◽

T Cell Development ◽

Γδ T Cells ◽

Cell Development ◽

Mtor Signaling ◽

Metabolic Reprogramming ◽

Metabolic Remodeling

The mechanistic target of rapamycin (mTOR) controls cell fate and responses via its functions in regulating metabolism. Its role in controlling immunity was unraveled by early studies on the immunosuppressive properties of rapamycin. Recent studies have provided insights on how metabolic reprogramming and mTOR signaling impact peripheral T cell activation and fate. The contribution of mTOR and metabolism during early T-cell development in the thymus is also emerging and is the subject of this review. Two major T lineages with distinct immune functions and peripheral homing organs diverge during early thymic development; the αβ- and γδ-T cells, which are defined by their respective TCR subunits. Thymic T-regulatory cells, which have immunosuppressive functions, also develop in the thymus from positively selected αβ-T cells. Here, we review recent findings on how the two mTOR protein complexes, mTORC1 and mTORC2, and the signaling molecules involved in the mTOR pathway are involved in thymocyte differentiation. We discuss emerging views on how metabolic remodeling impacts early T cell development and how this can be mediated via mTOR signaling.

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T Cell Development in Mice Lacking All T Cell Receptor ζ Family Members (ζ, η, and FcεRIγ)

Journal of Experimental Medicine ◽

10.1084/jem.187.7.1093 ◽

1998 ◽

Vol 187 (7) ◽

pp. 1093-1101 ◽

Cited By ~ 41

Author(s):

Elizabeth W. Shores ◽

Masao Ono ◽

Tsutomo Kawabe ◽

Connie L. Sommers ◽

Tom Tran ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Expression Patterns ◽

T Cell Development ◽

Cell Receptor ◽

Interferon Γ ◽

Cell Development ◽

Cell Populations ◽

Surface Complexes ◽

A Subunit

The ζ family includes ζ, η, and FcεRIγ (Fcγ). Dimers of the ζ family proteins function as signal transducing subunits of the T cell antigen receptor (TCR), the pre-TCR, and a subset of Fc receptors. In mice lacking ζ/η chains, T cell development is impaired, yet low numbers of CD4+ and CD8+ T cells develop. This finding suggests either that pre-TCR and TCR complexes lacking a ζ family dimer can promote T cell maturation, or that in the absence of ζ/η, Fcγ serves as a subunit in TCR complexes. To elucidate the role of ζ family dimers in T cell development, we generated mice lacking expression of all of these proteins and compared their phenotype to mice lacking only ζ/η or Fcγ. The data reveal that surface complexes that are expressed in the absence of ζ family dimers are capable of transducing signals required for α/β–T cell development. Strikingly, T cells generated in both ζ/η−/− and ζ/η−/−–Fcγ−/− mice exhibit a memory phenotype and elaborate interferon γ. Finally, examination of different T cell populations reveals that ζ/η and Fcγ have distinct expression patterns that correlate with their thymus dependency. A possible function for the differential expression of ζ family proteins may be to impart distinctive signaling properties to TCR complexes expressed on specific T cell populations.

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

Journal of Experimental Medicine ◽

10.1084/jem.194.7.903 ◽

2001 ◽

Vol 194 (7) ◽

pp. 903-914 ◽

Cited By ~ 56

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.

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