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Li J, Wachsmuth LP, Xiao S, Condie BG, Manley NR. Foxn1 overexpression promotes thymic epithelial progenitor cell proliferation and mTEC maintenance, but does not prevent thymic involution. Development 2023; 150:dev200995. [PMID: 36975725 PMCID: PMC10263147 DOI: 10.1242/dev.200995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 03/21/2023] [Indexed: 03/29/2023]
Abstract
The transcription factor FOXN1 is essential for fetal thymic epithelial cell (TEC) differentiation and proliferation. Postnatally, Foxn1 levels vary widely between TEC subsets, from low/undetectable in putative TEC progenitors to highest in differentiated TEC subsets. Correct Foxn1 expression is required to maintain the postnatal microenvironment; premature downregulation of Foxn1 causes a rapid involution-like phenotype, and transgenic overexpression can cause thymic hyperplasia and/or delayed involution. We investigated a K5.Foxn1 transgene that drives overexpression in mouse TECs, but causes neither hyperplasia nor delay or prevention of aging-related involution. Similarly, this transgene cannot rescue thymus size in Foxn1lacZ/lacZ mice, which undergo premature involution as a result of reduced Foxn1 levels. However, TEC differentiation and cortico-medullary organization are maintained with aging in both K5.Foxn1 and Foxn1lacZ/lacZ mice. Analysis of candidate TEC markers showed co-expression of progenitor and differentiation markers as well as increased proliferation in Plet1+ TECs associated with Foxn1 expression. These results demonstrate that the functions of FOXN1 in promoting TEC proliferation and differentiation are separable and context dependent, and suggest that modulating Foxn1 levels can regulate the balance of proliferation and differentiation in TEC progenitors.
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Affiliation(s)
- Jie Li
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | | | - Shiyun Xiao
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Brian G. Condie
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Nancy R. Manley
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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Muro R, Narita T, Nitta T, Takayanagi H. Spleen tyrosine kinase mediates the γδTCR signaling required for γδT cell commitment and γδT17 differentiation. Front Immunol 2023; 13:1045881. [PMID: 36713401 PMCID: PMC9878111 DOI: 10.3389/fimmu.2022.1045881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/23/2022] [Indexed: 01/13/2023] Open
Abstract
The γδT cells that produce IL-17 (γδT17 cells) play a key role in various pathophysiologic processes in host defense and homeostasis. The development of γδT cells in the thymus requires γδT cell receptor (γδTCR) signaling mediated by the spleen tyrosine kinase (Syk) family proteins, Syk and Zap70. Here, we show a critical role of Syk in the early phase of γδT cell development using mice deficient for Syk specifically in lymphoid lineage cells (Syk-conditional knockout (cKO) mice). The development of γδT cells in the Syk-cKO mice was arrested at the precursor stage where the expression of Rag genes and αβT-lineage-associated genes were retained, indicating that Syk is required for γδT-cell lineage commitment. Loss of Syk in γδT cells weakened TCR signal-induced phosphorylation of Erk and Akt, which is mandatory for the thymic development of γδT17 cells. Syk-cKO mice exhibited a loss of γδT17 cells in the thymus as well as throughout the body, and thereby are protected from γδT17-dependent psoriasis-like skin inflammation. Collectively, our results indicate that Syk is a key player in the lineage commitment of γδT cells and the priming of γδT17 cell differentiation.
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Affiliation(s)
- Ryunosuke Muro
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoya Narita
- Department of Pharmacotherapeutics, Research Institute of Pharmaceutical Sciences and Faculty of Pharmacy, Musashino University, Tokyo, Japan
| | - Takeshi Nitta
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan,*Correspondence: Takeshi Nitta,
| | - Hiroshi Takayanagi
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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Nguyen P, Pease NA, Kueh HY. Scalable control of developmental timetables by epigenetic switching networks. J R Soc Interface 2021; 18:20210109. [PMID: 34283940 DOI: 10.1098/rsif.2021.0109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
During development, progenitor cells follow timetables for differentiation that span many cell generations. These developmental timetables are robustly encoded by the embryo, yet scalably adjustable by evolution, facilitating variation in organism size and form. Epigenetic switches, involving rate-limiting activation steps at regulatory gene loci, control gene activation timing in diverse contexts, and could profoundly impact the dynamics of gene regulatory networks controlling developmental lineage specification. Here, we develop a mathematical framework to model regulatory networks with genes controlled by epigenetic switches. Using this framework, we show that such epigenetic switching networks uphold developmental timetables that robustly span many cell generations, and enable the generation of differentiated cells in precisely defined numbers and fractions. Changes to epigenetic switching networks can readily alter the timing of developmental events within a timetable, or alter the overall speed at which timetables unfold, enabling scalable control over differentiated population sizes. With their robust, yet flexibly adjustable nature, epigenetic switching networks could represent central targets on which evolution acts to manufacture diversity in organism size and form.
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Affiliation(s)
- Phuc Nguyen
- Molecular Engineering and Sciences Program, University of Washington, Seattle, WA, USA
| | - Nicholas A Pease
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Hao Yuan Kueh
- Department of Bioengineering, University of Washington, Seattle, WA, USA.,Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
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Hausinger R, Hackl M, Jardon Alvarez A, Kehr M, Romero Marquez S, Hettler F, Kehr C, Grziwok S, Schreck C, Peschel C, Istvánffy R, Oostendorp RAJ. Cathepsin K maintains the compartment of bone marrow T lymphocytes in vivo. IMMUNITY INFLAMMATION AND DISEASE 2021; 9:521-532. [PMID: 33592138 PMCID: PMC8127559 DOI: 10.1002/iid3.412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 01/03/2023]
Abstract
In this study, we investigated the influence of the loss of cathepsin K (Ctsk) gene on the hematopoietic system in vitro and in vivo. We found that cultures with lineage- SCA1+ KIT+ (LSK) cells on Ctsk deficient stromal cells display reduced colony formation and proliferation, with increased differentiation, giving rise to repopulating cells with reduced ability to repopulate the donor LSKs and T cell compartments in the bone marrow (BM). Subsequent in vivo experiments showed impairment of lymphocyte numbers, but, gross effects on early hematopoiesis or myelopoiesis were not found. Most consistently in in vivo experimental settings, we found a significant reduction of (donor) T cell numbers in the BM. Lymphocyte deregulation is also found in transplantation experiments, which revealed that Ctsk is required for optimal regeneration of small populations of T cells, particularly in the BM, but also of thymic B cells. Interestingly, cell nonautonomous Ctsk regulates both B and T cell numbers, but T cell numbers in the BM require an additional autonomous Ctsk-dependent process. Thus, we show that Ctsk is required for the maintenance of hematopoietic stem cells in vitro, but in vivo, Ctsk deficiency most strongly affects lymphocyte homeostasis, particularly of T cells in the BM.
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Affiliation(s)
- Renate Hausinger
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Marianne Hackl
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Ana Jardon Alvarez
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Miriam Kehr
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Sandra Romero Marquez
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Franziska Hettler
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Christian Kehr
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Sandra Grziwok
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Christina Schreck
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Christian Peschel
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Rouzanna Istvánffy
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
| | - Robert A J Oostendorp
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Internal Medicine III - Hematology and Oncology, Laboratory of Stem Cell Physiology, Munich, Germany
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