The canonical Wnt signaling pathway is mediated by interaction of β-catenin with the T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcription factors and subsequent transcription activation of Wnt-target genes. In the hematopoietic system, the function of the pathway has been mainly investigated by rather unspecific genetic manipulations of β-catenin that yielded contradictory results. Here, we used a mouse expressing a truncated dominant negative form of the human TCF4 transcription factor (dnTCF4) that specifically abrogates β-catenin-TCF/LEF interaction. Disruption of the β-catenin-TCF/LEF interaction resulted in the accumulation of immature cells and reduced granulocytic differentiation. Mechanistically, dnTCF4 progenitors exhibited downregulation of the Csf3r gene, reduced granulocyte colony-stimulating factor (G-CSF) receptor levels, attenuation of downstream Stat3 phosphorylation after G-CSF treatment, and impaired G-CSF-mediated differentiation. Chromatin immunoprecipitation assays confirmed direct binding of TCF/LEF factors to the promoter and putative enhancer regions of CSF3R. Inhibition of β-catenin signaling compromised activation of the emergency granulopoiesis program, which requires maintenance and expansion of myeloid progenitors. Consequently, dnTCF4 mice were more susceptible to Candida albicans infection and more sensitive to 5-fluorouracil-induced granulocytic regeneration. Importantly, genetic and chemical inhibition of β-catenin-TCF/LEF signaling in human CD34+ cells reduced granulocytic differentiation, whereas its activation enhanced myelopoiesis. Altogether, our data indicate that the β-catenin-TCF/LEF complex directly regulates G-CSF receptor levels, and consequently controls proper differentiation of myeloid progenitors into granulocytes in steady-state and emergency granulopoiesis. Our results uncover a role for the β-catenin signaling pathway in fine tuning the granulocytic production, opening venues for clinical intervention that require enhanced or reduced production of neutrophils.
- MeSH
- beta Catenin genetics metabolism MeSH
- Candida albicans MeSH
- Granulocytes metabolism MeSH
- Candidiasis genetics metabolism MeSH
- Myelopoiesis * MeSH
- Mice, Transgenic MeSH
- Mice MeSH
- Transcription Factor 7-Like 2 Protein metabolism MeSH
- Receptors, Colony-Stimulating Factor biosynthesis genetics MeSH
- Signal Transduction * MeSH
- TCF Transcription Factors genetics metabolism MeSH
- Up-Regulation * MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
The hypermethylated in cancer 1 (HIC1) gene is epigenetically inactivated in cancer, and in addition, the haploinsufficiency of HIC1 is linked to the development of human Miller-Dieker syndrome. HIC1 encodes a zinc-finger transcription factor that acts as a transcriptional repressor. Additionally, the HIC1 protein oligomerizes via the N-terminal BTB/POZ domain and forms discrete nuclear structures known as HIC1 bodies. Here, we provide evidence that HIC1 antagonizes the TCF/beta-catenin-mediated transcription in Wnt-stimulated cells. This appears to be due to the ability of HIC1 to associate with TCF-4 and to recruit TCF-4 and beta-catenin to the HIC1 bodies. As a result of the recruitment, both proteins are prevented from association with the TCF-binding elements of the Wnt-responsive genes. These data indicate that the intracellular amounts of HIC1 protein can modulate the level of the transcriptional stimulation of the genes regulated by canonical Wnt/beta-catenin signaling.
- MeSH
- beta Catenin genetics metabolism MeSH
- Cell Nucleus metabolism MeSH
- Cytoskeletal Proteins genetics metabolism MeSH
- DNA-Binding Proteins genetics metabolism MeSH
- Financing, Organized MeSH
- Transcription, Genetic MeSH
- Culture Media, Conditioned MeSH
- Humans MeSH
- Mice MeSH
- Promoter Regions, Genetic MeSH
- Wnt Proteins genetics metabolism MeSH
- Gene Expression Regulation MeSH
- RNA Interference MeSH
- Signal Transduction physiology MeSH
- Kruppel-Like Transcription Factors MeSH
- TCF Transcription Factors genetics metabolism MeSH
- Transcription Factors genetics metabolism MeSH
- Protein Binding MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
The interaction between vascular endothelial cells (ECs) and cancer cells is of vital importance to understand tumor dissemination. A paradigmatic cancer to study cell-cell interactions is classical Hodgkin Lymphoma (cHL) owing to its complex microenvironment. The role of the interplay between cHL and ECs remains poorly understood. Here we identify canonical WNT pathway activity as important for the mutual interactions between cHL cells and ECs. We demonstrate that local canonical WNT signaling activates cHL cell chemotaxis toward ECs, adhesion to EC layers and cell invasion using not only the Wnt-inhibitor Dickkopf, tankyrases and casein kinase 1 inhibitors but also knockdown of the lymphocyte enhancer binding-factor 1 (LEF-1) and β-catenin in cHL cells. Furthermore, LEF-1- and β-catenin-regulated cHL secretome promoted EC migration, sprouting and vascular tube formation involving vascular endothelial growth factor A (VEGF-A). Importantly, high VEGFA expression is associated with a worse overall survival of cHL patients. These findings strongly support the concept that WNTs might function as a regulator of lymphoma dissemination by affecting cHL cell chemotaxis and promoting EC behavior and thus angiogenesis through paracrine interactions.
- MeSH
- beta Catenin genetics metabolism MeSH
- Cell Adhesion genetics MeSH
- Cell Line MeSH
- Chemokine CCL19 metabolism MeSH
- Chemotaxis genetics immunology MeSH
- Endothelial Cells metabolism MeSH
- Hodgkin Disease genetics immunology metabolism pathology MeSH
- Humans MeSH
- Cell Communication * MeSH
- Tumor Microenvironment * genetics immunology MeSH
- Neovascularization, Pathologic MeSH
- Cell Movement genetics MeSH
- Wnt Signaling Pathway * MeSH
- Lymphoid Enhancer-Binding Factor 1 genetics metabolism MeSH
- Vascular Endothelial Growth Factor A metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Diffuse large B-cell lymphoma (DLBCL) represents the most common adult lymphoma and can be divided into 2 major molecular subtypes: the germinal center B-cell-like and the aggressive activated B-cell-like (ABC) DLBCL. Previous studies suggested that chronic B-cell receptor signaling and increased NF-κB activation contribute to ABC DLBCL survival. Here we show that the activity of the transcription factor NFAT is chronically elevated in both DLBCL subtypes. Surprisingly, NFAT activation is independent of B-cell receptor signaling, but mediated by an increased calcium flux and calcineurin-mediated dephosphorylation of NFAT. Intriguingly, although NFAT is activated in both DLBCL subtypes, long-term calcineurin inhibition with cyclosporin A or FK506, both clinically approved drugs, triggers potent cytotoxicity specifically in ABC DLBCL cells. The antitumor effects of calcineurin inhibitors are associated with the reduced expression of c-Jun, interleukin-6, and interleukin-10, which were identified as NFAT target genes that are particularly important for the survival of ABC DLBCL. Furthermore, calcineurin blockade synergized with BCL-2 and MCL-1 inhibitors in killing ABC DLBCL cells. Collectively, these findings identify constitutive NFAT signaling as a crucial functional driver of ABC DLBCL and highlight calcineurin inhibition as a novel strategy for the treatment of this aggressive lymphoma subtype.
- MeSH
- Lymphoma, Large B-Cell, Diffuse drug therapy metabolism pathology MeSH
- Calcineurin Inhibitors pharmacology MeSH
- Calcineurin chemistry MeSH
- Humans MeSH
- Tumor Cells, Cultured MeSH
- Cell Proliferation MeSH
- Myeloid Cell Leukemia Sequence 1 Protein genetics metabolism MeSH
- Proto-Oncogene Proteins c-bcl-2 genetics metabolism MeSH
- NFATC Transcription Factors antagonists & inhibitors metabolism MeSH
- Calcium metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The Wnt/β-catenin signaling pathway controls many processes during development, including cell proliferation, cell differentiation and tissue homeostasis, and its aberrant regulation has been linked to various pathologies. In this study we investigated the effect of ectopic activation of Wnt/β-catenin signaling during lens fiber cell differentiation. To activate Wnt/β-catenin signaling in lens fiber cells, the transgenic mouse referred to as αA-CLEF was generated, in which the transactivation domain of β-catenin was fused to the DNA-binding protein LEF1, and expression of the transgene was controlled by αA-crystallin promoter. Constitutive activation of Wnt/β-catenin signaling in lens fiber cells of αA-CLEF mice resulted in abnormal and delayed fiber cell differentiation. Moreover, adult αA-CLEF mice developed cataract, microphthalmia and manifested downregulated levels of γ-crystallins in lenses. We provide evidence of aberrant expression of cell cycle regulators in embryonic lenses of αA-CLEF transgenic mice resulting in the delay in cell cycle exit and in the shift of fiber cell differentiation to the central fiber cell compartment. Our results indicate that precise regulation of the Wnt/β-catenin signaling activity during later stages of lens development is essential for proper lens fiber cell differentiation and lens transparency.
- MeSH
- beta Catenin genetics metabolism MeSH
- Cell Differentiation genetics MeSH
- Cell Cycle genetics MeSH
- DNA-Binding Proteins genetics metabolism MeSH
- Epithelial Cells metabolism MeSH
- Cataract genetics metabolism MeSH
- Crystallins genetics metabolism MeSH
- Humans MeSH
- Microphthalmos genetics metabolism MeSH
- Mice, Inbred C57BL MeSH
- Mice, Transgenic genetics metabolism MeSH
- Mice MeSH
- Lens, Crystalline metabolism MeSH
- Promoter Regions, Genetic genetics MeSH
- Wnt Signaling Pathway genetics MeSH
- Signal Transduction genetics MeSH
- Lymphoid Enhancer-Binding Factor 1 MeSH
- Gene Expression Regulation, Developmental MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) proteins (TCFs) from the High Mobility Group (HMG) box family act as the main downstream effectors of the Wnt signaling pathway. The mammalian TCF/LEF family comprises four nuclear factors designated TCF7, LEF1, TCF7L1, and TCF7L2 (also known as TCF1, LEF1, TCF3, and TCF4, respectively). The proteins display common structural features and are often expressed in overlapping patterns implying their redundancy. Such redundancy was indeed observed in gene targeting studies; however, individual family members also exhibit unique features that are not recapitulated by the related proteins. In the present viewpoint, we summarized our current knowledge about the specific features of individual TCFs, namely structural-functional studies, posttranslational modifications, interacting partners, and phenotypes obtained upon gene targeting in the mouse. In addition, we employed several publicly available databases and web tools to evaluate the expression patterns and production of gene-specific isoforms of the TCF/LEF family members in human cells and tissues.
- Publication type
- Journal Article MeSH
- Review MeSH
T-cell factor 4 (TCF4), together with β-catenin coactivator, functions as the major transcriptional mediator of the canonical wingless/integrated (Wnt) signaling pathway in the intestinal epithelium. The pathway activity is essential for both intestinal homeostasis and tumorigenesis. To date, several mouse models and cellular systems have been used to analyze TCF4 function. However, some findings were conflicting, especially those that were related to the defects observed in the mouse gastrointestinal tract after Tcf4 gene deletion, or to a potential tumor suppressive role of the gene in intestinal cancer cells or tumors. Here, we present the results obtained using a newly generated conditional Tcf4 allele that allows inactivation of all potential Tcf4 isoforms in the mouse tissue or small intestinal and colon organoids. We also employed the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system to disrupt the TCF4 gene in human cells. We showed that in adult mice, epithelial expression of Tcf4 is indispensable for cell proliferation and tumor initiation. However, in human cells, the TCF4 role is redundant with the related T-cell factor 1 (TCF1) and lymphoid enhancer-binding factor 1 (LEF1) transcription factors.
- Publication type
- Journal Article MeSH
... cells by influencing both peptide binding and the contacts between T-cell receptor and MHC molecule. ... ... /threonine kinase Akt. 7-18 T-cell receptor signaling leads to enhanced integrin-mediated cell adhesion ... ... T-cell activation. 7-22 Maximal activation of PLC-y, which is important for transcription factor activation ... ... T-cell ? ... ... -cell and T-cell areas in secondary lymphoid tissues. 403 -- 10-4 T cells express surface molecules and ...
9th edition xx, 904 stran : ilustrace, tabulky ; 28 cm
- Conspectus
- Patologie. Klinická medicína
- NML Fields
- alergologie a imunologie
- biologie
- fyziologie
- NML Publication type
- kolektivní monografie
... Organ Where T Cells Mature -- Secondary Lymphoid Organs: Where the Immune Response Is Initiated • ... ... Activators -- Helper CD4+ T-Cell Differentiation • Helper T Cells Can Be Divided into Distinct Subsets ... ... T Cells May Not Be Irrevocably Committed to a Lineage 381 • Helper T-Cell Subsets Play Critical Roles ... ... Cell Responses • T-lndependent Antigens Stimulate Antibody Production in the Absence of T-Cell Help ... ... Processed Antigen Travel to the T-Cell Zones of Secondary Lymphoid Tissue 525 • Unprocessed Antigen ...
Eight edition různé stránkování : barevné ilustrace ; 28 cm
- MeSH
- Allergy and Immunology MeSH
- Immune System MeSH
- Publication type
- Textbook MeSH
- Conspectus
- Patologie. Klinická medicína
- Učební osnovy. Vyučovací předměty. Učebnice
- NML Fields
- alergologie a imunologie
... Cells 15 2.1 Form of Antigen Recognized by T Cells 15 2.2 MHC Molecules 16 2.3 MHC Loci 16 2.4 Structure ... ... Activation by Antigen 25 3.1 Categories ofT Cells 25 3.2 Structure of T-Cell Receptors 25 3.3 Antigen ... ... Binding by B Cells 41 -- 4.6 B-Cell Activation 41 -- 4.6 a T-Dependent Antigens and Haptens 42 -- 4.6 ... ... Lymphocytes 69 -- 6.1 The Main Sites of B- and T-Lymphocyte -- Maturation 69 -- 6.2 T-Cell Maturation ... ... -- 6.10 a CD5* B (B-1) Cells 84 -- 6.10 b Extrathymic T Cells 84 -- 6.11 Concluding Remarks 84 -- Study ...
303 s. : il.
