25 results on '"Outram SV"'
Search Results
2. BMP signals: Mediated by stroma or thymocytes?
- Author
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Outram SV, Chen D, and Umukoro C
- Subjects
- Animals, Humans, Bone Morphogenetic Protein 2 metabolism, Bone Morphogenetic Protein 4 metabolism, Bone Morphogenetic Protein Receptors, Type I metabolism, CD4 Antigens metabolism, CD8 Antigens metabolism, Hematopoietic Stem Cells cytology, T-Lymphocytes cytology
- Published
- 2014
- Full Text
- View/download PDF
3. Regulation of murine normal and stress-induced erythropoiesis by Desert Hedgehog.
- Author
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Lau CI, Outram SV, Saldaña JI, Furmanski AL, Dessens JT, and Crompton T
- Subjects
- Age Factors, Animals, Bone Marrow metabolism, Bone Marrow radiation effects, Cell Differentiation genetics, Cell Differentiation physiology, Cell Differentiation radiation effects, Cells, Cultured, Erythroblasts metabolism, Erythroblasts physiology, Erythroblasts radiation effects, Erythropoiesis physiology, Erythropoiesis radiation effects, Hedgehog Proteins genetics, Hedgehog Proteins metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, Recovery of Function genetics, Recovery of Function physiology, Signal Transduction genetics, Signal Transduction physiology, Signal Transduction radiation effects, Spleen metabolism, Spleen radiation effects, Stress, Physiological genetics, Stress, Physiological radiation effects, Whole-Body Irradiation, Erythropoiesis genetics, Hedgehog Proteins physiology, Stress, Physiological physiology
- Abstract
The function of Hedgehog signaling in hematopoiesis is controversial, with different experimental systems giving opposing results. Here we examined the role of Desert Hedgehog (Dhh) in the regulation of murine erythropoiesis. Dhh is one of 3 mammalian Hedgehog family proteins. Dhh is essential for testis development and Schwann cell function. We show, by analysis of Dhh-deficient mice, that Dhh negatively regulates multiple stages of erythrocyte differentiation. In Dhh-deficient bone marrow, the common myeloid progenitor (CMP) population was increased, but differentiation from CMP to granulocyte/macrophage progenitor was decreased, and the mature granulocyte population was decreased, compared with wild-type (WT). In contrast, differentiation from CMP to megakaryocyte/erythrocyte progenitor was increased, and the megakaryocyte/erythrocyte progenitor population was increased. In addition, we found that erythroblast populations were Dhh-responsive in vitro and ex vivo and that Dhh negatively regulated erythroblast differentiation. In Dhh-deficient spleen and bone marrow, BFU-Es and erythroblast populations were increased compared with WT. During recovery of hematopoiesis after irradiation, and under conditions of stress-induced erythropoiesis, erythrocyte differentiation was accelerated in both spleen and bone marrow of Dhh-deficient mice compared with WT.
- Published
- 2012
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4. Non-redundant role for the transcription factor Gli1 at multiple stages of thymocyte development.
- Author
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Drakopoulou E, Outram SV, Rowbotham NJ, Ross SE, Furmanski AL, Saldana JI, Hager-Theodorides AL, and Crompton T
- Subjects
- Animals, Biomarkers metabolism, Female, Hedgehog Proteins metabolism, Kruppel-Like Transcription Factors genetics, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Thymus Gland metabolism, Zinc Finger Protein GLI1, Cell Differentiation physiology, Kruppel-Like Transcription Factors metabolism, Signal Transduction physiology, T-Lymphocytes physiology, Thymus Gland cytology, Thymus Gland embryology, Thymus Gland growth & development
- Abstract
The Hedgehog (Hh) signaling pathway influences multiple stages of murine T-cell development. Hh signaling mediates transcriptional changes by the activity of the Gli family of transcription factors, Gli1, Gli2 and Gli3. Both Gli2 and Gli3 are essential for mouse development and can be processed to function as transcriptional repressors or transcriptional activators, whereas Gli1, itself a transcriptional target of Hh pathway activation, can only function as a transcriptional activator and is not essential for mouse development. Gli1-deficient mice are healthy and appear normal and nonredundant functions for Gli1 have been difficult to identify. Here we show that Gli1 is non-redundant in the regulation of T-cell development in the thymus, at multiple developmental stages. Analysis of Gli1-deficient embryonic mouse thymus shows a role for Gli1 to promote the differentiation of CD4⁻CD8⁻ double negative (DN) thymocytes before pre- TCR signal transduction, and a negative regulatory function after pre-TCR signaling. In addition, introduction of a Class I-restricted transgenic TCR into the adult Gli1-deficient and embryonic Gli2-deficient thymus showed that both Gli1 and Gli2 influence its selection to the CD8 lineage.
- Published
- 2010
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5. The Gli3 transcription factor expressed in the thymus stroma controls thymocyte negative selection via Hedgehog-dependent and -independent mechanisms.
- Author
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Hager-Theodorides AL, Furmanski AL, Ross SE, Outram SV, Rowbotham NJ, and Crompton T
- Subjects
- Animals, Autoimmune Diseases immunology, Autoimmune Diseases metabolism, Cell Differentiation genetics, Female, Gene Expression Regulation, Developmental immunology, Growth Inhibitors biosynthesis, Growth Inhibitors genetics, Kruppel-Like Transcription Factors biosynthesis, Kruppel-Like Transcription Factors genetics, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, Nerve Tissue Proteins biosynthesis, Nerve Tissue Proteins genetics, Organ Culture Techniques, Receptors, Antigen, T-Cell biosynthesis, Receptors, Antigen, T-Cell physiology, Stromal Cells immunology, Stromal Cells metabolism, Thymus Gland cytology, Zinc Finger Protein Gli3, Cell Differentiation immunology, Growth Inhibitors physiology, Hedgehog Proteins physiology, Kruppel-Like Transcription Factors physiology, Nerve Tissue Proteins physiology, Thymus Gland immunology, Thymus Gland metabolism
- Abstract
The Hedgehog (Hh) responsive transcription factor Gli3 is required for efficient thymocyte development in the fetus. In this study we show that Gli3, not detected in adult thymocytes, is expressed in the murine fetal and adult thymus stroma. PCR array analysis revealed Cxcl9, Rbp1, and Nos2 as novel target genes of Gli3. We show that Gli3 positively regulates the expression of these genes, most likely by suppressing an intermediate repressor. Deletion of autoreactive thymocytes depends on their interactions with the thymus stroma. Repression of the proapoptotic gene Nos2 in Gli3 mutants coincides with reduced apoptosis of double positive thymocytes undergoing negative selection in vitro and in vivo, and the production of autoreactive thymocytes. Taken together these data indicate that Gli3 controls thymocyte apoptosis and negative selection possibly via the regulation of Nos2. Defective Gli3 expression in the thymus stroma also resulted in decreased CD5 expression on mature thymocytes and inappropriate production of MHC class I-selected CD4(+) cells, both consistent with reduced TCR signal strength. Overall our data indicate that Gli3 expressed in the thymus stroma regulates negative selection and TCR signal strength via Hh-dependent and -independent mechanisms, with implications for autoimmunity.
- Published
- 2009
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6. Sonic hedgehog negatively regulates pre-TCR-induced differentiation by a Gli2-dependent mechanism.
- Author
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Rowbotham NJ, Hager-Theodorides AL, Furmanski AL, Ross SE, Outram SV, Dessens JT, and Crompton T
- Subjects
- Animals, Gene Expression Profiling, Hedgehog Proteins deficiency, Hepatocyte Nuclear Factor 3-beta genetics, Kruppel-Like Transcription Factors deficiency, Mice, Mice, Transgenic, Receptors, Antigen, T-Cell, Signal Transduction, Thymus Gland cytology, Transcription Factors genetics, Zinc Finger Protein Gli2, Cell Differentiation immunology, Hedgehog Proteins physiology, Kruppel-Like Transcription Factors physiology
- Abstract
Hedgehog signaling regulates differentiation, survival, and proliferation of the earliest double-negative (DN) thymocytes, but its importance at later stages of T-cell development is controversial. Here we use loss- and gain-of-function mouse models to show that Shh, by signaling directly to the developing thymocyte, is a negative regulator of pre-TCR-induced differentiation from DN to double-positive (DP) cell. When hedgehog signaling was reduced, in the Shh(-/-) and Gli2(-/-) thymus, or by T lineage-specific transgenic expression of a transcriptional-repressor form of Gli2 (Gli2DeltaC(2)), differentiation to DP cell after pre-TCR signal transduction was increased. In contrast, when Hh signaling was constitutively activated in thymocytes, by transgenic expression of a constitutive transcriptional-activator form of Gli2 (Gli2DeltaN(2)), the production of DP cells was decreased. Gene expression profiling showed that physiologic Hh signaling in thymocytes maintains expression of the transcription factor FoxA2 on pre-TCR signal transduction.
- Published
- 2009
- Full Text
- View/download PDF
7. Indian hedgehog (Ihh) both promotes and restricts thymocyte differentiation.
- Author
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Outram SV, Hager-Theodorides AL, Shah DK, Rowbotham NJ, Drakopoulou E, Ross SE, Lanske B, Dessens JT, and Crompton T
- Subjects
- Animals, Antigens, CD biosynthesis, Fetus, Flow Cytometry, Gene Rearrangement, T-Lymphocyte, Hedgehog Proteins genetics, Homeostasis immunology, Kruppel-Like Transcription Factors biosynthesis, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, Antigen, T-Cell genetics, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction immunology, Thymus Gland embryology, Thymus Gland growth & development, Zinc Finger Protein GLI1, Cell Differentiation immunology, Hedgehog Proteins metabolism, T-Lymphocytes cytology, Thymus Gland cytology
- 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.
- Published
- 2009
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8. KLF13 influences multiple stages of both B and T cell development.
- Author
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Outram SV, Gordon AR, Hager-Theodorides AL, Metcalfe J, Crompton T, and Kemp P
- Subjects
- Animals, B-Lymphocytes immunology, CD5 Antigens metabolism, Cell Differentiation, Kruppel-Like Transcription Factors deficiency, Lymphocyte Activation physiology, Mice, Mice, Knockout, Receptors, Complement 3d metabolism, Receptors, IgE metabolism, T-Lymphocyte Subsets immunology, B-Lymphocytes metabolism, Cell Cycle Proteins metabolism, Kruppel-Like Transcription Factors metabolism, Receptors, Antigen, T-Cell metabolism, Repressor Proteins metabolism, T-Lymphocyte Subsets metabolism, Thymus Gland metabolism
- Abstract
The Kruppel-like factor, KLF13, is a member of a family of transcription factors shown to be involved in haematopoietic development. Here we show that KLF13 is involved in the development of B and T cells at multiple stages. Expression of KLF13 in the thymus was maximal in the DP population and in KLF13(-/-) deficient mice there was an accumulation of DP thymocytes and reduction of CD4(+)SP cells. Cell-surface expression of CD3(high), CD8, CD5 and HSA were altered on KLF13(-/-) DP cells, consistent with a defect in TCR signalling and at the DP to SP transition in KLF13(-/-) mice. KLF13 is also expressed in peripheral T-cells and peripheral T cell activation was impaired in KLF13(-/-) mice. Analysis of early B cell development in the bone marrow (BM) revealed a partial arrest of B cells at the transition from CD43(+) to CD43(-) pre-B cell, a transition that requires signalling through the pre-BCR. The proportion of IgM(+)/IgD(+) mature B cells was also increased in the BM of the KLF13(-/-) mice. This finding is consistent with a reduction in the strength of BCR signal or an accumulation of recirculating B cells from the periphery. Analysis of splenocytes isolated from KLF13(-/-) mice revealed an increase in the expression of CD21 and CD23 on B220(+) B cells, demonstrating a negative regulatory role for KLF13 in co-regulation of expression of CD21 and CD23. Thus KLF13 is involved at multiple different checkpoints in development that require signalling through the TCR, pre-BCR or mature BCR.
- Published
- 2008
- Full Text
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9. Splenomegaly and modified erythropoiesis in KLF13-/- mice.
- Author
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Gordon AR, Outram SV, Keramatipour M, Goddard CA, Colledge WH, Metcalfe JC, Hager-Theodorides AL, Crompton T, and Kemp PR
- Subjects
- Animals, Apoptosis genetics, Base Sequence, Blood Cell Count, Bone Marrow pathology, Cell Cycle Proteins genetics, Cell Differentiation, Cell Proliferation, Erythroblasts pathology, Gene Deletion, Gene Expression Regulation, Gene Targeting, Genotype, Kruppel-Like Transcription Factors genetics, Mice, Mice, Knockout, Molecular Sequence Data, Organ Size, RNA, Messenger genetics, RNA, Messenger metabolism, Repressor Proteins genetics, Splenomegaly pathology, Erythropoiesis, Kruppel-Like Transcription Factors deficiency, Splenomegaly physiopathology
- Abstract
To study the function of the Krüppel-like transcription factor KLF13 in vivo, we generated mice with a disrupted Klf13 allele. Although Klf13(-/-) mice are viable, fewer mice were present at 3 weeks than predicted by Mendelian inheritance. Viable Klf13(-/-) mice had reduced numbers of circulating erythrocytes and a larger spleen. The spleen contained an increased number of Ter119(med)CD71(hi), Ter119(hi)CD71(hi), and Ter119(hi)CD71(med) cells but not Ter119(hi)CD71(-) cells, indicating an increase in less mature erythroblasts. A higher proportion of the Ter119(med)CD71(hi) cells were proliferating, indicating that the mice were under a degree of erythropoietic stress. These data indicate that KLF13 is involved in the normal control of erythropoiesis.
- Published
- 2008
- Full Text
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10. Repression of hedgehog signal transduction in T-lineage cells increases TCR-induced activation and proliferation.
- Author
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Rowbotham NJ, Furmanski AL, Hager-Theodorides AL, Ross SE, Drakopoulou E, Koufaris C, Outram SV, and Crompton T
- Subjects
- Animals, DNA Primers genetics, Genotype, Kruppel-Like Transcription Factors metabolism, Mice, Mice, Transgenic, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction genetics, Zinc Finger Protein Gli2, Cell Differentiation immunology, Hedgehog Proteins metabolism, Signal Transduction physiology, T-Lymphocytes cytology, T-Lymphocytes metabolism
- Abstract
Hedgehog proteins signal for differentiation, survival and proliferation of the earliest thymocyte progenitors, but their functions at later stages of thymocyte development and in peripheral T-cell function are controversial. Here we show that repression of Hedgehog (Hh) pathway activation in T-lineage cells, by expression of a transgenic repressor form of Gli2 (Gli2DeltaC2), increased T-cell differentiation and activation in response to TCR signalling. Expression of the Gli2DeltaC2 transgene increased differentiation from CD4(+)CD8(+) to single positive thymocyte, and increased peripheral T cell populations. Gli2DeltaC2 T-cells were hyper-responsive to activation by ligation of CD3 and CD28: they expressed cell surface activation markers CD69 and CD25 more quickly, and proliferated more than wild-type T-cells. These data show that Hedgehog pathway activation in thymocytes and T-cells negatively regulates TCR-dependent differentiation and proliferation. Thus, as negative regulators of TCR-dependent events, Hh proteins provide an environmental influence on T-cell fate.
- Published
- 2008
- Full Text
- View/download PDF
11. Sonic hedgehog signalling in T-cell development and activation.
- Author
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Crompton T, Outram SV, and Hager-Theodorides AL
- Subjects
- Animals, Fetus immunology, Humans, Signal Transduction, Hedgehog Proteins metabolism, Lymphocyte Activation, T-Lymphocytes immunology, Thymus Gland immunology
- Abstract
The production of mature functional T cells in the thymus requires signals from the thymic epithelium. Here, we review recent experiments showing that one way in which the epithelium controls the production of mature T cells is by the secretion of sonic hedgehog (SHH). We consider the increasing evidence that SHH-induced signalling is not only important for the differentiation and proliferation of early thymocyte progenitors, but also for modulating T-cell receptor signalling during repertoire selection, with implications for positive selection, CD4 versus CD8 lineage commitment, and clonal deletion of autoreactive cells. We also review the influence of hedgehog signalling in peripheral T-cell activation.
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- 2007
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12. Activation of the Hedgehog signaling pathway in T-lineage cells inhibits TCR repertoire selection in the thymus and peripheral T-cell activation.
- Author
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Rowbotham NJ, Hager-Theodorides AL, Cebecauer M, Shah DK, Drakopoulou E, Dyson J, Outram SV, and Crompton T
- Subjects
- Animals, CD4-Positive T-Lymphocytes metabolism, CD5 Antigens immunology, CD5 Antigens metabolism, CD8-Positive T-Lymphocytes metabolism, Cell Proliferation, Extracellular Signal-Regulated MAP Kinases immunology, Extracellular Signal-Regulated MAP Kinases metabolism, Hedgehog Proteins deficiency, Hedgehog Proteins metabolism, Kruppel-Like Transcription Factors deficiency, Kruppel-Like Transcription Factors immunology, Lymphocyte Activation genetics, MAP Kinase Signaling System genetics, Mice, Mice, Transgenic, Organ Culture Techniques, Receptors, Antigen, T-Cell, Thymus Gland growth & development, Zinc Finger Protein Gli2, CD4-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes immunology, Hedgehog Proteins immunology, Lymphocyte Activation immunology, MAP Kinase Signaling System immunology, Thymus Gland immunology
- Abstract
TCR signal strength is involved in many cell fate decisions in the T-cell lineage. Here, we show that transcriptional events induced by Hedgehog (Hh) signaling reduced TCR signal strength in mice. Activation of Hh signaling in thymocytes in vivo by expression of a transgenic transcriptional-activator form of Gli2 (Gli2DeltaN(2)) changed the outcome of TCR ligation at many stages of thymocyte development, allowing self-reactive cells to escape clonal deletion; reducing transgenic TCR-mediated positive selection; reducing the ratio of CD4/CD8 single-positive (SP) cells; and reducing cell surface CD5 expression. In contrast, in the Shh(-/-) thymus the ratio of CD4/CD8 cells and both positive and negative selection of a transgenic TCR were increased, demonstrating that Shh does indeed influence TCR repertoire selection and the transition from double-positive (DP) to SP cell in a physiological situation. In peripheral T cells, Gli2DeltaN(2) expression attenuated T-cell activation and proliferation, by a mechanism upstream of ERK phosphorylation.
- Published
- 2007
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13. Beta-selection: abundance of TCRbeta-/gammadelta- CD44- CD25- (DN4) cells in the foetal thymus.
- Author
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Hager-Theodorides AL, Rowbotham NJ, Outram SV, Dessens JT, and Crompton T
- Subjects
- Animals, Cell Lineage immunology, Fetus, Flow Cytometry, Hyaluronan Receptors immunology, Interleukin-2 Receptor alpha Subunit immunology, Mice, Receptors, Antigen, T-Cell genetics, Reverse Transcriptase Polymerase Chain Reaction, T-Lymphocyte Subsets immunology, T-Lymphocytes immunology, Thymus Gland immunology, Cell Differentiation immunology, Gene Rearrangement, beta-Chain T-Cell Antigen Receptor immunology, Receptors, Antigen, T-Cell immunology, T-Lymphocyte Subsets cytology, T-Lymphocytes cytology, Thymus Gland cytology
- Abstract
Expression of TCRbeta and pre-TCR signalling are essential for differentiation of CD4- CD8- double negative (DN) thymocytes to the CD4+ CD8+ double-positive (DP) stage. Thymocyte development in adult Rag1, Rag2 or TCRbetadelta-deficient mice is arrested at the DN3 stage leading to the assumption that pre-TCR signalling and beta-selection occur at, and are obligatory for, the transition from DN3 to DN4. We show that the majority of DN3 and DN4 cells that differentiate during early embryogenesis in wild-type mice do not express intracellular (ic) TCRbeta/gammadelta. These foetal icTCRbeta-/gammadelta- DN4 cells were T lineage as determined by expression of Thy1 and icCD3 and TCRbeta DJ rearrangement. In addition, in the foetal Rag1-/- thymus, a normal percentage of DN4 cells were present. In wild-type mice after hydrocortisone-induced synchronisation of differentiation, the majority of DN4 cells that first emerged did not express icTCRbeta/gammadelta, showing that adult thymocytes can also differentiate to the DN4 stage independently of pre-TCR signalling. Pre-TCR signalling induced expansion in the DN4 population, but lack of TCRbeta/gammadelta expression did not immediately induce apoptosis. Our data demonstrate in vivo differentiation from DN3 to DN4 cell in the absence of TCRbeta/gammadelta expression in the foetal thymus, and after hydrocortisone treatment of adult mice.
- Published
- 2007
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14. The transcription factor Gli3 regulates differentiation of fetal CD4- CD8- double-negative thymocytes.
- Author
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Hager-Theodorides AL, Dessens JT, Outram SV, and Crompton T
- Subjects
- Animals, CD4 Antigens, CD8 Antigens, Cell Lineage, Embryo, Mammalian cytology, Embryo, Mammalian immunology, Gene Expression Regulation, Developmental, Kruppel-Like Transcription Factors, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Thymus Gland embryology, Thymus Gland growth & development, Zinc Finger Protein Gli3, Antigens, CD analysis, Cell Differentiation, DNA-Binding Proteins physiology, Nerve Tissue Proteins physiology, T-Lymphocytes cytology, Thymus Gland cytology, Transcription Factors physiology
- Abstract
Glioblastoma 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.
- Published
- 2005
- Full Text
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15. Sonic hedgehog is produced by follicular dendritic cells and protects germinal center B cells from apoptosis.
- Author
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Sacedón R, Díez B, Nuñez V, Hernández-López C, Gutierrez-Frías C, Cejalvo T, Outram SV, Crompton T, Zapata AG, Vicente A, and Varas A
- Subjects
- Animals, Antibodies, Blocking pharmacology, Antibody Formation drug effects, Antibody Formation immunology, Cell Survival drug effects, Cell Survival immunology, Cells, Cultured, Female, Germinal Center immunology, Growth Inhibitors pharmacology, Hedgehog Proteins, Lymph Nodes cytology, Lymph Nodes metabolism, Mice, Mice, Inbred BALB C, Signal Transduction drug effects, Signal Transduction immunology, Spleen cytology, Spleen metabolism, Trans-Activators antagonists & inhibitors, Trans-Activators immunology, Up-Regulation, Veratrum Alkaloids pharmacology, Apoptosis immunology, B-Lymphocyte Subsets cytology, B-Lymphocyte Subsets metabolism, Dendritic Cells, Follicular metabolism, Germinal Center cytology, Germinal Center metabolism, Trans-Activators biosynthesis, Trans-Activators physiology
- Abstract
The Hedgehog (Hh) signaling pathway is involved in the development of many tissues during embryogenesis, but has also been described to function in adult self-renewing tissues. In the immune system, Sonic Hedgehog (Shh) regulates intrathymic T cell development and modulates the effector functions of peripheral CD4(+) T cells. In this study we investigate whether Shh signaling is involved in peripheral B cell differentiation in mice. Shh is produced by follicular dendritic cells, mainly in germinal centers (GCs), and GC B cells express both components of the Hh receptor, Patched and Smoothened. Blockade of the Hh signaling pathway reduces the survival, and consequently the proliferation and Ab secretion, of GC B cells. Furthermore, Shh rescues GC B cells from apoptosis induced by Fas ligation. Taken together, our data suggest that Shh is one of the survival signals provided by follicular dendritic cells to prevent apoptosis in GC B cells.
- Published
- 2005
- Full Text
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16. Reduced thymocyte development in sonic hedgehog knockout embryos.
- Author
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Shah DK, Hager-Theodorides AL, Outram SV, Ross SE, Varas A, and Crompton T
- Subjects
- Animals, Cell Differentiation genetics, Cell Differentiation immunology, Cell Division genetics, Cell Division immunology, Dose-Response Relationship, Immunologic, Down-Regulation genetics, Embryo, Mammalian metabolism, Embryo, Mammalian pathology, Female, Fetal Tissue Transplantation immunology, Fetus, Hedgehog Proteins, Liver Transplantation immunology, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Knockout, Organ Culture Techniques, Receptors, Interleukin-2 biosynthesis, Signal Transduction genetics, Signal Transduction immunology, T-Lymphocyte Subsets metabolism, Thymus Gland metabolism, Thymus Gland radiation effects, Trans-Activators pharmacology, Down-Regulation immunology, Embryo, Mammalian immunology, T-Lymphocyte Subsets immunology, T-Lymphocyte Subsets pathology, Thymus Gland immunology, Thymus Gland pathology, Trans-Activators deficiency, Trans-Activators genetics
- Abstract
The Hedgehog family of secreted intercellular signaling molecules are regulators of patterning and organogenesis during animal development. In this study we provide genetic evidence that Sonic Hedgehog (Shh) has a role in the control of murine T cell development. Analysis of Shh(-/-) mouse embryos revealed that Shh regulates fetal thymus cellularity and thymocyte differentiation. Shh is necessary for expansion of CD4(-)CD8(-) double-negative (DN) thymocytes and for efficient transition from the earliest CD44(+)CD25(-) DN population to the subsequent CD44(+)CD25(+) DN population and from DN to CD4(+)CD8(+) double-positive cells.
- Published
- 2004
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17. Bone morphogenetic protein 2/4 signaling regulates early thymocyte differentiation.
- Author
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Hager-Theodorides AL, Outram SV, Shah DK, Sacedon R, Shrimpton RE, Vicente A, Varas A, and Crompton T
- Subjects
- Activin Receptors, Type I biosynthesis, Activin Receptors, Type I genetics, Adjuvants, Immunologic pharmacology, Adjuvants, Immunologic physiology, Animals, Bone Morphogenetic Protein 2, Bone Morphogenetic Protein 4, Bone Morphogenetic Protein Receptors, Type I, Bone Morphogenetic Proteins antagonists & inhibitors, Carrier Proteins, Cell Differentiation genetics, Cell Differentiation immunology, Cell Survival genetics, Cell Survival immunology, Cells, Cultured, Dose-Response Relationship, Immunologic, Fetus, Gene Expression Regulation immunology, Genes, T-Cell Receptor beta genetics, Genes, T-Cell Receptor delta genetics, Growth Inhibitors physiology, Hyaluronan Receptors biosynthesis, Hyaluronan Receptors metabolism, Mice, Mice, Inbred BALB C, Mice, Knockout, Organ Culture Techniques, Proteins pharmacology, Receptors, Interleukin-2 biosynthesis, Receptors, Interleukin-2 metabolism, Recombinant Fusion Proteins pharmacology, Signal Transduction genetics, T-Lymphocytes metabolism, Thymus Gland metabolism, Bone Morphogenetic Proteins physiology, Protein Serine-Threonine Kinases, Receptors, Growth Factor, Signal Transduction immunology, T-Lymphocytes cytology, Thymus Gland cytology, Transforming Growth Factor beta
- Abstract
Bone morphogenetic protein (BMP)2 and BMP4 are involved in the development of many tissues. In this study, we show that BMP2/4 signaling is involved in thymocyte development. Our data suggest that termination of BMP2/4 signaling is necessary for differentiation of CD44(+)CD25(-)CD4(-)CD8(-) double negative (DN) cells along the T cell lineage. BMP2 and BMP4 are produced by the thymic stroma and the requisite BMP receptor molecules (BMPR-1A, BMPR-1B, BMPR-II), and signal transduction molecules (Smad-1, -5, -8, and -4) are expressed by DN thymocytes. BMP4 inhibits thymocyte proliferation, enhances thymocyte survival, and arrests thymocyte differentiation at the CD44(+)CD25(-) DN stage, before T cell lineage commitment. Neutralization of endogenous BMP2 and BMP4 by treatment with the antagonist Noggin promotes and accelerates thymocyte differentiation, increasing the expression of CD2 and the proportion of CD44(-)CD25(-) DN cells and CD4(+)CD8(+) double-positive cells. Our study suggests that the BMP2/4 pathway may function in thymic homeostasis by regulating T cell lineage commitment and differentiation.
- Published
- 2002
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18. The T-lineage-affiliated CD2 gene lies within an open chromatin environment in acute promyelocytic leukemia cells.
- Author
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Grimwade D, Outram SV, Flora R, Ings SJ, Pizzey AR, Morilla R, Craddock CF, Linch DC, and Solomon E
- Subjects
- Cell Lineage, Chromatin chemistry, Chromatin genetics, Deoxyribonuclease I metabolism, Humans, Immunophenotyping, Jurkat Cells, Leukemia, Promyelocytic, Acute pathology, Polymerase Chain Reaction methods, T-Lymphocytes cytology, CD2 Antigens genetics, Chromatin physiology, Leukemia, Promyelocytic, Acute genetics, T-Lymphocytes physiology
- Abstract
The nature of hemopoietic progenitors subject to leukemic transformation in acute myeloid leukemia (AML) has not been clearly defined. To address this issue, we have used DNase I hypersensitivity assays to study the chromatin structure surrounding the T-lineage-affiliated CD2 gene in the acute promyelocytic subtype of AML (APL). Upstream and downstream flanking regions of CD2 were found to be hypersensitive to DNase I in primary APL blasts, with an identical pattern of hypersensitive sites to those detected in cells of T-lineage. All of the sites were confirmed to be inaccessible to DNase I in B-lineage leukemia cells. The demonstration of T-cell-associated chromatin features in primary APL blasts has implications for the origin of APL that may arise in more primitive progenitors than previously considered to be the case.
- Published
- 2002
19. Diacylglycerol kinase alpha activity promotes survival of CD4+ 8+ double positive cells during thymocyte development.
- Author
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Outram SV, Crompton T, Merida I, Varas A, and Martinez-A C
- Subjects
- Animals, CD4-Positive T-Lymphocytes cytology, CD4-Positive T-Lymphocytes enzymology, CD8-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes enzymology, Cell Differentiation, Cell Survival drug effects, Cells, Cultured, Diacylglycerol Kinase antagonists & inhibitors, Diacylglycerol Kinase genetics, Enzyme Inhibitors pharmacology, Gene Expression Regulation, Genes, bcl-2, Isoenzymes antagonists & inhibitors, Isoenzymes genetics, Isoenzymes metabolism, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) genetics, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) metabolism, Mice, Mice, Inbred BALB C, Mice, Transgenic, Piperidines pharmacology, Proto-Oncogene Proteins c-bcl-2 genetics, Quinazolines pharmacology, Quinazolinones, T-Lymphocytes cytology, bcl-X Protein, Diacylglycerol Kinase metabolism, Receptors, Antigen, T-Cell, alpha-beta metabolism, Signal Transduction physiology, T-Lymphocytes enzymology
- Abstract
The diacylglycerol kinases (DGK) form a family of isoenzymes that catalyse the conversion of diacylglycerol (DAG) to phosphatidic acid (PA), both powerful second messengers in the cell. DGKalpha is expressed in brain, peripheral T cells and thymocytes and has been shown to translocate to the nuclear matrix upon T-cell receptor (TCR) engagement. Here, we show that high level expression of DGKalpha is induced following a signal transmitted through the pre-TCR and the protein tyrosine kinase, lck. Activity of DGKalpha contributes to survival in CD4+ 8+ (DP) thymocytes as pharmacological inhibition of DGK activity results in death of this cell population both in cell suspension and thymic explants. DGKalpha promotes survival in these thymocytes through a Bcl-regulated pathway. A consequence of inhibition of DGKalpha is the specific down-regulation of Bcl-xl, whereas in transgenic mice that over-express Bcl-2, death induced by the inhibitor is partially blocked. Thus we report a novel activity of DGKalpha in survival of thymocytes immediately after entry into the DP stage in development.
- Published
- 2002
- Full Text
- View/download PDF
20. Repression of CD2 gene expression is mediated by an AP-2 related factor.
- Author
-
Outram SV, Grimwade D, and Crompton T
- Subjects
- Base Sequence, Binding Sites genetics, CCAAT-Enhancer-Binding Proteins metabolism, CD2 Antigens metabolism, Cell Extracts, Cell Nucleus metabolism, Chloramphenicol O-Acetyltransferase genetics, Chloramphenicol O-Acetyltransferase metabolism, DNA Footprinting, DNA-Binding Proteins genetics, Deoxyribonuclease I, Gene Expression Regulation, Humans, Jurkat Cells, Molecular Sequence Data, Mutation, NFI Transcription Factors, Nuclear Proteins metabolism, Promoter Regions, Genetic genetics, Protein Binding, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Regulatory Sequences, Nucleic Acid genetics, Transcription Factor AP-2, Transcription Factors genetics, Transcription, Genetic, Transfection, CD2 Antigens genetics, DNA-Binding Proteins metabolism, Transcription Factors metabolism
- Abstract
Tissue specific and developmental expression of the CD2 gene is tightly regulated during T cell development. DNase I hypersensitivity analysis has revealed the presence of two sites (DHS1 and 2) located 5' to the CD2 gene which have been reported to be implicated in the developmental regulation of expression of CD2. The location of DHS2 marks the position of the minimal promoter whereas DHS1 is located approximately 1800 bp upstream. We show that repressor and derepressor activities are contained within the region of DNA marked by DHS1. The repressor is capable of regulating homologous and heterologous promoters regardless of orientation. This activity is entirely dependent upon the presence of an AP-2 binding site as mutation of this site resulted in a loss of repressor activity. A nuclear factor found in Jurkat cells specifically binds this site but was shown to be serologically distinct from AP-2., (Copyright 2001 Academic Press.)
- Published
- 2001
- Full Text
- View/download PDF
21. Erratum.
- Author
-
Outram SV, Varas A, Pepicelli CV, and Crompton T
- Published
- 2000
- Full Text
- View/download PDF
22. Hedgehog signaling regulates differentiation from double-negative to double-positive thymocyte.
- Author
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Outram SV, Varas A, Pepicelli CV, and Crompton T
- Subjects
- Animals, CD4 Antigens physiology, CD8 Antigens physiology, Cell Differentiation physiology, Hedgehog Proteins, Mice, Mice, Inbred BALB C, Thymus Gland embryology, Proteins physiology, Signal Transduction physiology, T-Lymphocyte Subsets cytology, T-Lymphocyte Subsets physiology, Thymus Gland cytology, Thymus Gland physiology, Trans-Activators
- Abstract
The hedgehog (Hh) signaling pathway is involved in the development of many tissues. Here we show that sonic hedgehog (Shh) is involved in thymocyte development. Our data suggest that termination of Hh signaling is necessary for differentiation from CD4-CD8-double-negative (DN) to CD4+CD8+ double-positive (DP) thymocyte. Shh is produced by the thymic stroma, and Patched and Smoothened (Smo), the transmembrane receptors for Shh, are expressed in DN thymocytes. A neutralizing monoclonal antibody against Shh increases differentiation of DN to DP thymocytes, and Shh protein arrests thymocyte differentiation at the CD25+ DN stage, after T cell receptor beta (TCRbeta) gene rearrangement. We show that one consequence of pre-TCR signaling is downregulation of Smo, allowing DN thymocytes to proliferate and differentiate.
- Published
- 2000
- Full Text
- View/download PDF
23. Distinct roles of the interleukin-7 receptor alpha chain in fetal and adult thymocyte development revealed by analysis of interleukin-7 receptor alpha-deficient mice.
- Author
-
Crompton T, Outram SV, Buckland J, and Owen MJ
- Subjects
- Animals, Antigens, CD genetics, Cell Differentiation, Mice, Receptors, Antigen, T-Cell, gamma-delta immunology, Receptors, Interleukin genetics, Receptors, Interleukin-7, Thymus Gland cytology, Antigens, CD immunology, Receptors, Interleukin immunology, T-Lymphocytes immunology, Thymus Gland immunology
- Abstract
Mouse mutants lacking expression of the IL-7 receptor (IL-7R) alpha chain are defective in thymopoiesis. The adult thymus has multiple defects, including reduced cell numbers and proportions of the more mature thymocyte subsets, a complete absence of CD25+ cells and a reduced level of RAG1 and RAG2 expression. We show here that, in contrast to the profound developmental arrest observed in the adult thymus, fetal thymocytes from IL-7Ralpha-/- mice have normal proportions of all of the major thymocyte subpopulations, including CD25+ thymocytes and the most mature single-positive subsets. Moreover, normal levels of RAG1 and RAG2 were observed. Total thymocyte numbers, however, remained reduced. These data suggest that the IL-7Ralpha chain is a key regulator of both survival and proliferation during thymocyte development but that it is not essential for the production of T cells during fetal thymopoiesis.
- Published
- 1998
- Full Text
- View/download PDF
24. A transgenic T cell receptor restores thymocyte differentiation in interleukin-7 receptor alpha chain-deficient mice.
- Author
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Crompton T, Outram SV, Buckland J, and Owen MJ
- Subjects
- Animals, DNA-Binding Proteins, Gene Expression, Hematopoiesis, Mice, Mice, Transgenic, Proteins genetics, RNA, Messenger genetics, Receptors, Interleukin-7, Signal Transduction, Thymus Gland embryology, Antigens, CD metabolism, Gene Rearrangement, T-Lymphocyte, Homeodomain Proteins, Interleukin-7 physiology, Receptors, Antigen, T-Cell physiology, Receptors, Interleukin metabolism, T-Lymphocyte Subsets cytology, Thymus Gland cytology
- Abstract
Interleukin-7 (IL-7) receptor alpha chain-deficient (IL-7R alpha-/-) mice have severely depleted lymphocyte populations and thymocyte development is arrested at the double-negative (DN) stage. We show that thymocyte development in these mice can be reconstituted by the introduction of a transgenic T cell receptor (TCR), implying that one function of the IL-7R alpha chain is to initiate TCR gene rearrangement. Expression of the recombinase-activating genes RAG1 and RAG2 was greatly reduced in the IL-7R alpha-/- thymuses, and in DN thymocytes from the TCR transgenic IL-7R alpha-/- mice, but was restored in double-positive thymocytes from the TCR transgenic IL-7R alpha-/- mice. These data suggest that the IL-7R alpha chain controls RAG expression and initiation of TCR beta chain VDJ rearrangement in DN cells. In contrast, once cells have progressed beyond the DN stage of development the IL-7R alpha chain becomes no longer essential for RAG expression.
- Published
- 1997
- Full Text
- View/download PDF
25. The helix-loop-helix containing transcription factor USF activates the promoter of the CD2 gene.
- Author
-
Outram SV and Owen MJ
- Subjects
- Base Sequence, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors, Basic-Leucine Zipper Transcription Factors, Cells, Cultured, DNA-Binding Proteins metabolism, Humans, Molecular Sequence Data, Transcription, Genetic, Transcriptional Activation, Upstream Stimulatory Factors, CD2 Antigens genetics, Helix-Loop-Helix Motifs, Promoter Regions, Genetic, Transcription Factors physiology
- Abstract
T cell development within the thymus involves the ordered expression of a number of tissue-specific components such as the CD2 gene. Control of expression of this gene is regulated by a well characterized 3' enhancer together with a promoter and upstream elements. The CD2 promoter is typical of a group of T cell-specific promoters that lack a TATA box and use multiple sites for initiation of transcription. An "E box" motif CACGTG, located just upstream from the most 5' initiation start site, was found to contribute a major effect to the level of basal transcription of a reporter gene. Analysis of the proteins in T cell extracts that bound to this site revealed that the bHLH-LZ protein USF was the major component. A functional role for USF was established in transient transfection experiments. Thus, this protein restored full promoter activity following repression caused by cotransfection with the E box binding bHLH-LZ protein Max. Taken together, these results indicate that an E box motif is critical to expression of the CD2 gene during T cell development and that the HLH protein USF acts as a transcriptional activator of the CD2 promoter.
- Published
- 1994
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