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Vesala L, Basikhina Y, Tuomela T, Nurminen A, Siukola E, Vale PF, Salminen TS. Mitochondrial perturbation in immune cells enhances cell-mediated innate immunity in Drosophila. BMC Biol 2024; 22:60. [PMID: 38475850 DOI: 10.1186/s12915-024-01858-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Mitochondria participate in various cellular processes including energy metabolism, apoptosis, autophagy, production of reactive oxygen species, stress responses, inflammation and immunity. However, the role of mitochondrial metabolism in immune cells and tissues shaping the innate immune responses are not yet fully understood. We investigated the effects of tissue-specific mitochondrial perturbation on the immune responses at the organismal level. Genes for oxidative phosphorylation (OXPHOS) complexes cI-cV were knocked down in the fruit fly Drosophila melanogaster, targeting the two main immune tissues, the fat body and the immune cells (hemocytes). RESULTS While OXPHOS perturbation in the fat body was detrimental, hemocyte-specific perturbation led to an enhanced immunocompetence. This was accompanied by the formation of melanized hemocyte aggregates (melanotic nodules), a sign of activation of cell-mediated innate immunity. Furthermore, the hemocyte-specific OXPHOS perturbation induced immune activation of hemocytes, resulting in an infection-like hemocyte profile and an enhanced immune response against parasitoid wasp infection. In addition, OXPHOS perturbation in hemocytes resulted in mitochondrial membrane depolarization and upregulation of genes associated with the mitochondrial unfolded protein response. CONCLUSIONS Overall, we show that while the effects of mitochondrial perturbation on immune responses are highly tissue-specific, mild mitochondrial dysfunction can be beneficial in immune-challenged individuals and contributes to variation in infection outcomes among individuals.
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Affiliation(s)
- Laura Vesala
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Yuliya Basikhina
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Tea Tuomela
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Anssi Nurminen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Emilia Siukola
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Pedro F Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Tiina S Salminen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
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2
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Ready DF, Chang HC. Interommatidial cells build a tensile collagen network during Drosophila retinal morphogenesis. Curr Biol 2023; 33:2223-2234.e3. [PMID: 37209679 PMCID: PMC10247444 DOI: 10.1016/j.cub.2023.04.066] [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: 09/02/2022] [Revised: 03/27/2023] [Accepted: 04/27/2023] [Indexed: 05/22/2023]
Abstract
Drosophila compound eye morphogenesis transforms a simple epithelium into an approximate hollow hemisphere comprised of ∼700 ommatidia, packed as tapering hexagonal prisms between a rigid external array of cuticular lenses and a parallel, rigid internal floor, the fenestrated membrane (FM). Critical to vision, photosensory rhabdomeres are sprung between these two surfaces, grading their length and shape accurately across the eye and aligning them to the optical axis. Using fluorescently tagged collagen and laminin, we show that that the FM assembles sequentially, emerging in the larval eye disc in the wake of the morphogenetic furrow as the original collagen-containing basement membrane (BM) separates from the epithelial floor and is replaced by a new, laminin-rich BM, which advances around axon bundles of newly differentiated photoreceptors as they exit the retina, forming fenestrae in this new, laminin-rich BM. In mid-pupal development, the interommatidial cells (IOCs) autonomously deposit collagen at fenestrae, forming rigid, tension-resisting grommets. In turn, stress fibers assemble in the IOC basal endfeet, where they contact grommets at anchorages mediated by integrin linked kinase (ILK). The hexagonal network of IOC endfeet tiling the retinal floor couples nearest-neighbor grommets into a supracellular tri-axial tension network. Late in pupal development, IOC stress fiber contraction folds pliable BM into a hexagonal grid of collagen-stiffened ridges, concomitantly decreasing the area of convex FM and applying essential morphogenetic longitudinal tension to rapidly growing rhabdomeres. Together, our results reveal an orderly program of sequential assembly and activation of a supramolecular tensile network that governs Drosophila retinal morphogenesis.
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Affiliation(s)
- Donald F Ready
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA
| | - Henry C Chang
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA.
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3
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Zhang K, Tan J, Hao X, Tang H, Abbas MN, Su J, Su Y, Cui H. Bombyx mori U-shaped regulates the melanization cascade and immune response via binding with the Lozenge protein. INSECT SCIENCE 2022; 29:704-716. [PMID: 34331739 DOI: 10.1111/1744-7917.12959] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/01/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Zinc finger protein, an important transcription factor, regulates gene expression associated with various physiological and pathological processes. U-shaped, belong to the Friend of GATA (FOG) transcription factor, plays a crucial role in hematopoiesis by interacting with the GATA transcription factor as a co-factor. However, little is known about its functions in insects. In the present study, a U-shaped cDNA was identified and characterized from the silkworm Bombyx mori and its potential roles in innate immunity investigated. The predicted silkworm U-shaped amino acid sequence contained a classical nuclear localization signal (NLS) motif "GESSPKRRRR" at position 450-459, and arginine residues at position 456 and 478 are the critical sites of the NLS. U-shaped mRNA was detected in all tested tissues of the B. mori; however, the highest levels were found in the hemocytes. U-shaped mRNA expression levels were upregulated in the hemocyte after the Escherichia coli and Staphylococcus aureus challenge. Furthermore, U-shaped knockdown significantly reduced the melanization process and suppressed the expression of melanization-associated genes, including PPO1, PPO2, PPAE and BAEE. In addition, U-shaped interacts with Lozenge protein to regulate the innate immune response of the insect. Our results revealed that U-shaped binds directly to Lozenge protein to modulate the melanization process and innate immune responses in silkworm.
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Affiliation(s)
- Kui Zhang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
| | - Juan Tan
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
| | - Xiangwei Hao
- Chongqing Reproductive and Genetics Institute, Chongqing Obstetrics and Gynecology Hospital, Chongqing, 400013, China
| | - Houyi Tang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
| | - Muhammad Nadeem Abbas
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
| | - Jingjing Su
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
| | - Yongyue Su
- Department of Orthopaedic, 920th Hospital of Joint Logistics Support Force of Chinese People's Liberation Army, Kunming, 650032, China
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400716, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, 400716, China
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4
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Moussalem D, Augé B, Di Stefano L, Osman D, Gobert V, Haenlin M. Two Isoforms of serpent Containing Either One or Two GATA Zinc Fingers Provide Functional Diversity During Drosophila Development. Front Cell Dev Biol 2022; 9:795680. [PMID: 35178397 PMCID: PMC8844375 DOI: 10.3389/fcell.2021.795680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/29/2021] [Indexed: 11/13/2022] Open
Abstract
GATA transcription factors play crucial roles in various developmental processes in organisms ranging from flies to humans. In mammals, GATA factors are characterized by the presence of two highly conserved domains, the N-terminal (N-ZnF) and the C-terminal (C-ZnF) zinc fingers. The Drosophila GATA factor Serpent (Srp) is produced in different isoforms that contains either both N-ZnF and C-ZnF (SrpNC) or only the C-ZnF (SrpC). Here, we investigated the functional roles ensured by each of these isoforms during Drosophila development. Using the CRISPR/Cas9 technique, we generated new mutant fly lines deleted for one (ΔsrpNC) or the other (ΔsrpC) encoded isoform, and a third one with a single point mutation in the N-ZnF that alters its interaction with its cofactor, the Drosophila FOG homolog U-shaped (Ush). Analysis of these mutants revealed that the Srp zinc fingers are differentially required for Srp to fulfill its functions. While SrpC is essential for embryo to adult viability, SrpNC, which is the closest conserved isoform to that of vertebrates, is not. However, to ensure its specific functions in larval hematopoiesis and fertility, Srp requires the presence of both N- and C-ZnF (SrpNC) and interaction with its cofactor Ush. Our results also reveal that in vivo the presence of N-ZnF restricts rather than extends the ability of GATA factors to regulate the repertoire of C-ZnF bound target genes.
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Affiliation(s)
- Douaa Moussalem
- Molecular, Cellular and Developmental Biology Department (MCD), Center for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Benoit Augé
- Molecular, Cellular and Developmental Biology Department (MCD), Center for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Luisa Di Stefano
- Molecular, Cellular and Developmental Biology Department (MCD), Center for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Dani Osman
- Faculty of Sciences III, Lebanese University, Tripoli, Lebanon.,Azm Center for Research in Biotechnology and Its Applications, LBA3B, EDST, Lebanese University, Tripoli, Lebanon
| | - Vanessa Gobert
- Molecular, Cellular and Developmental Biology Department (MCD), Center for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Marc Haenlin
- Molecular, Cellular and Developmental Biology Department (MCD), Center for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
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5
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Järvelä-Stölting M, Vesala L, Maasdorp MK, Ciantar J, Rämet M, Valanne S. Proteasome α6 Subunit Negatively Regulates the JAK/STAT Pathway and Blood Cell Activation in Drosophila melanogaster. Front Immunol 2021; 12:729631. [PMID: 35003057 PMCID: PMC8727353 DOI: 10.3389/fimmu.2021.729631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
JAK/STAT signaling regulates central biological functions such as development, cell differentiation and immune responses. In Drosophila, misregulated JAK/STAT signaling in blood cells (hemocytes) induces their aberrant activation. Using mass spectrometry to analyze proteins associated with a negative regulator of the JAK/STAT pathway, and by performing a genome-wide RNAi screen, we identified several components of the proteasome complex as negative regulators of JAK/STAT signaling in Drosophila. A selected proteasome component, Prosα6, was studied further. In S2 cells, Prosα6 silencing decreased the amount of the known negative regulator of the pathway, ET, leading to enhanced expression of a JAK/STAT pathway reporter gene. Silencing of Prosα6 in vivo resulted in activation of the JAK/STAT pathway, leading to the formation of lamellocytes, a specific hemocyte type indicative of hemocyte activation. This hemocyte phenotype could be partially rescued by simultaneous knockdown of either the Drosophila STAT transcription factor, or MAPKK in the JNK-pathway. Our results suggest a role for the proteasome complex components in the JAK/STAT pathway in Drosophila blood cells both in vitro and in vivo.
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Affiliation(s)
- Mirva Järvelä-Stölting
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Laura Vesala
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Matthew K. Maasdorp
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Joanna Ciantar
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Mika Rämet
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, Faculty of Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu, Oulu, Finland
- Department of Children and Adolescents, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Susanna Valanne
- Laboratory of Experimental Immunology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- *Correspondence: Susanna Valanne,
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6
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Wang L, Liu F, Zhang G, Su H, Sun J. A novel Ush transcription factor involving in hematopoiesis of Eriocheir sinensis. Comp Biochem Physiol B Biochem Mol Biol 2021; 259:110703. [PMID: 34915123 DOI: 10.1016/j.cbpb.2021.110703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/04/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022]
Abstract
The FOG transcriptional factor is a co-regulator that recognizes and binds to the GATA N-terminal zinc-finger domain and participates in hemocyte production and differentiation. In this study, an FOG-like gene, Ush, was characterized from Eriocheir sinensis, which consists of an 897 bp full-length open reading frame, encoding a polypeptide of 298 amino acids with four ZnF_C2H2 domains. The EsUsh mRNA transcripts were mainly expressed in the hematopoietic tissue (HPT) and hemocytes, and were significantly higher in hyalinocytes than semi-granulocytes and granulocytes, which were separated by Percoll gradient centrifugation. The transcription levels of EsUsh were found to be significantly upregulated in HPT, but downregulated in hemocytes after exsanguination. By using flow cytometry to determine the percentage of hemocyte sub-population after exsanguination, the percentage of hyalinocytes was found to significantly downregulated, while the percentage of granulocytes was significantly upregulated. Silencing EsUsh by dsRNA interference significantly decreased the percentage of hyalinocytes and small granulocytes, and increased the percentage of medium granulocytes and large granulocytes. Such findings suggest that EsUsh might be involved in hemocyte production and differentiation, especially in promoting hyalinocyte formation and limiting granulocyte generation and differentiation.
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Affiliation(s)
- Liyan Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China,.
| | - Fang Liu
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China
| | - Guangcheng Zhang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China
| | - Hui Su
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China
| | - Jinsheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China,.
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7
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Boulet M, Renaud Y, Lapraz F, Benmimoun B, Vandel L, Waltzer L. Characterization of the Drosophila Adult Hematopoietic System Reveals a Rare Cell Population With Differentiation and Proliferation Potential. Front Cell Dev Biol 2021; 9:739357. [PMID: 34722521 PMCID: PMC8550105 DOI: 10.3389/fcell.2021.739357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/22/2021] [Indexed: 02/06/2023] Open
Abstract
While many studies have described Drosophila embryonic and larval blood cells, the hematopoietic system of the imago remains poorly characterized and conflicting data have been published concerning adult hematopoiesis. Using a combination of blood cell markers, we show that the adult hematopoietic system is essentially composed of a few distinct mature blood cell types. In addition, our transcriptomics results indicate that adult and larval blood cells have both common and specific features and it appears that adult hemocytes reactivate many genes expressed in embryonic blood cells. Interestingly, we identify a small set of blood cells that does not express differentiation markers but rather maintains the expression of the progenitor marker domeMeso. Yet, we show that these cells are derived from the posterior signaling center, a specialized population of cells present in the larval lymph gland, rather than from larval blood cell progenitors, and that their maintenance depends on the EBF transcription factor Collier. Furthermore, while these cells are normally quiescent, we find that some of them can differentiate and proliferate in response to bacterial infection. In sum, our results indicate that adult flies harbor a small population of specialized cells with limited hematopoietic potential and further support the idea that no substantial hematopoiesis takes place during adulthood.
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Affiliation(s)
- Manon Boulet
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - Yoan Renaud
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - François Lapraz
- Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Billel Benmimoun
- Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Laurence Vandel
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - Lucas Waltzer
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France.,Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
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8
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Buchberger E, Bilen A, Ayaz S, Salamanca D, Matas de las Heras C, Niksic A, Almudi I, Torres-Oliva M, Casares F, Posnien N. Variation in Pleiotropic Hub Gene Expression Is Associated with Interspecific Differences in Head Shape and Eye Size in Drosophila. Mol Biol Evol 2021; 38:1924-1942. [PMID: 33386848 PMCID: PMC8097299 DOI: 10.1093/molbev/msaa335] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Revealing the mechanisms underlying the breathtaking morphological diversity observed in nature is a major challenge in Biology. It has been established that recurrent mutations in hotspot genes cause the repeated evolution of morphological traits, such as body pigmentation or the gain and loss of structures. To date, however, it remains elusive whether hotspot genes contribute to natural variation in the size and shape of organs. As natural variation in head morphology is pervasive in Drosophila, we studied the molecular and developmental basis of differences in compound eye size and head shape in two closely related Drosophila species. We show differences in the progression of retinal differentiation between species and we applied comparative transcriptomics and chromatin accessibility data to identify the GATA transcription factor Pannier (Pnr) as central factor associated with these differences. Although the genetic manipulation of Pnr affected multiple aspects of dorsal head development, the effect of natural variation is restricted to a subset of the phenotypic space. We present data suggesting that this developmental constraint is caused by the coevolution of expression of pnr and its cofactor u-shaped (ush). We propose that natural variation in expression or function of highly connected developmental regulators with pleiotropic functions is a major driver for morphological evolution and we discuss implications on gene regulatory network evolution. In comparison to previous findings, our data strongly suggest that evolutionary hotspots are not the only contributors to the repeated evolution of eye size and head shape in Drosophila.
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Affiliation(s)
- Elisa Buchberger
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
| | - Anıl Bilen
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
| | - Sanem Ayaz
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
| | - David Salamanca
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
- Present address: Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | | | - Armin Niksic
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
| | - Isabel Almudi
- CABD (CSIC/UPO/JA), DMC2 Unit, Pablo de Olavide University Campus, Seville, Spain
| | - Montserrat Torres-Oliva
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
- Present address: Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Fernando Casares
- CABD (CSIC/UPO/JA), DMC2 Unit, Pablo de Olavide University Campus, Seville, Spain
| | - Nico Posnien
- Department of Developmental Biology, University of Göttingen, Göttingen, Germany
- Corresponding author: E-mail:
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9
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Coates JA, Brooks E, Brittle AL, Armitage EL, Zeidler MP, Evans IR. Identification of functionally distinct macrophage subpopulations in Drosophila. eLife 2021; 10:e58686. [PMID: 33885361 PMCID: PMC8062135 DOI: 10.7554/elife.58686] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 03/30/2021] [Indexed: 12/24/2022] Open
Abstract
Vertebrate macrophages are a highly heterogeneous cell population, but while Drosophila blood is dominated by a macrophage-like lineage (plasmatocytes), until very recently these cells were considered to represent a homogeneous population. Here, we present our identification of enhancer elements labelling plasmatocyte subpopulations, which vary in abundance across development. These subpopulations exhibit functional differences compared to the overall population, including more potent injury responses and differential localisation and dynamics in pupae and adults. Our enhancer analysis identified candidate genes regulating plasmatocyte behaviour: pan-plasmatocyte expression of one such gene (Calnexin14D) improves wound responses, causing the overall population to resemble more closely the subpopulation marked by the Calnexin14D-associated enhancer. Finally, we show that exposure to increased levels of apoptotic cell death modulates subpopulation cell numbers. Taken together this demonstrates macrophage heterogeneity in Drosophila, identifies mechanisms involved in subpopulation specification and function and facilitates the use of Drosophila to study macrophage heterogeneity in vivo.
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Affiliation(s)
- Jonathon Alexis Coates
- Department of Biomedical Science and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Elliot Brooks
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Amy Louise Brittle
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Emma Louise Armitage
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Martin Peter Zeidler
- Department of Biomedical Science and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Iwan Robert Evans
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
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10
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Ush regulates hemocyte-specific gene expression, fatty acid metabolism and cell cycle progression and cooperates with dNuRD to orchestrate hematopoiesis. PLoS Genet 2021; 17:e1009318. [PMID: 33600407 PMCID: PMC7891773 DOI: 10.1371/journal.pgen.1009318] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/20/2020] [Indexed: 12/13/2022] Open
Abstract
The generation of lineage-specific gene expression programmes that alter proliferation capacity, metabolic profile and cell type-specific functions during differentiation from multipotent stem cells to specialised cell types is crucial for development. During differentiation gene expression programmes are dynamically modulated by a complex interplay between sequence-specific transcription factors, associated cofactors and epigenetic regulators. Here, we study U-shaped (Ush), a multi-zinc finger protein that maintains the multipotency of stem cell-like hemocyte progenitors during Drosophila hematopoiesis. Using genomewide approaches we reveal that Ush binds to promoters and enhancers and that it controls the expression of three gene classes that encode proteins relevant to stem cell-like functions and differentiation: cell cycle regulators, key metabolic enzymes and proteins conferring specific functions of differentiated hemocytes. We employ complementary biochemical approaches to characterise the molecular mechanisms of Ush-mediated gene regulation. We uncover distinct Ush isoforms one of which binds the Nucleosome Remodeling and Deacetylation (NuRD) complex using an evolutionary conserved peptide motif. Remarkably, the Ush/NuRD complex specifically contributes to the repression of lineage-specific genes but does not impact the expression of cell cycle regulators or metabolic genes. This reveals a mechanism that enables specific and concerted modulation of functionally related portions of a wider gene expression programme. Finally, we use genetic assays to demonstrate that Ush and NuRD regulate enhancer activity during hemocyte differentiation in vivo and that both cooperate to suppress the differentiation of lamellocytes, a highly specialised blood cell type. Our findings reveal that Ush coordinates proliferation, metabolism and cell type-specific activities by isoform-specific cooperation with an epigenetic regulator.
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11
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Cho B, Yoon SH, Lee D, Koranteng F, Tattikota SG, Cha N, Shin M, Do H, Hu Y, Oh SY, Lee D, Vipin Menon A, Moon SJ, Perrimon N, Nam JW, Shim J. Single-cell transcriptome maps of myeloid blood cell lineages in Drosophila. Nat Commun 2020; 11:4483. [PMID: 32900993 PMCID: PMC7479620 DOI: 10.1038/s41467-020-18135-y] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/06/2020] [Indexed: 11/22/2022] Open
Abstract
The Drosophila lymph gland, the larval hematopoietic organ comprised of prohemocytes and mature hemocytes, has been a valuable model for understanding mechanisms underlying hematopoiesis and immunity. Three types of mature hemocytes have been characterized in the lymph gland: plasmatocytes, lamellocytes, and crystal cells, which are analogous to vertebrate myeloid cells, yet molecular underpinnings of the lymph gland hemocytes have been less investigated. Here, we use single-cell RNA sequencing to comprehensively analyze heterogeneity of developing hemocytes in the lymph gland, and discover previously undescribed hemocyte types including adipohemocytes, stem-like prohemocytes, and intermediate prohemocytes. Additionally, we identify the developmental trajectory of hemocytes during normal development as well as the emergence of the lamellocyte lineage following active cellular immunity caused by wasp infestation. Finally, we establish similarities and differences between embryonically derived- and larval lymph gland hemocytes. Altogether, our study provides detailed insights into the hemocyte development and cellular immune responses at single-cell resolution. How the Drosophila lymph gland hemocytes develop and are regulated at a single-cell level is unclear. Here, the authors use single-cell RNA sequencing to show heterogeneity of developing hemocytes in the lymph gland and how they react to wasp infestation, and compare hemocytes from two independent origins.
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Affiliation(s)
- Bumsik Cho
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Sang-Ho Yoon
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Daewon Lee
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Ferdinand Koranteng
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | | | - Nuri Cha
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Mingyu Shin
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Hobin Do
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Yanhui Hu
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Sue Young Oh
- Department of Oral Biology, Yonsei University, College of Dentistry, Seoul, 03722, Republic of Korea
| | - Daehan Lee
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - A Vipin Menon
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea
| | - Seok Jun Moon
- Department of Oral Biology, Yonsei University, College of Dentistry, Seoul, 03722, Republic of Korea
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA.,Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Jin-Wu Nam
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea. .,Research Institute for Natural Sciences, Hanyang University, Seoul, 04736, Republic of Korea. .,Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04736, Republic of Korea.
| | - Jiwon Shim
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, 04736, Republic of Korea. .,Research Institute for Natural Sciences, Hanyang University, Seoul, 04736, Republic of Korea. .,Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04736, Republic of Korea.
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12
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Lan W, Liu S, Zhao L, Su Y. Regulation of Drosophila Hematopoiesis in Lymph Gland: From a Developmental Signaling Point of View. Int J Mol Sci 2020; 21:ijms21155246. [PMID: 32722007 PMCID: PMC7432643 DOI: 10.3390/ijms21155246] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 12/15/2022] Open
Abstract
The Drosophila hematopoietic system is becoming increasingly attractive for its simple blood cell lineage and its developmental and functional parallels with the vertebrate system. As the dedicated organ for Drosophila larval hematopoiesis, the lymph gland harbors both multipotent stem-like progenitor cells and differentiated blood cells. The balance between progenitor maintenance and differentiation in the lymph gland must be precisely and tightly controlled. Multiple developmental signaling pathways, such as Notch, Hedgehog, and Wnt/Wingless, have been demonstrated to regulate the hematopoietic processes in the lymph gland. Focusing on blood cell maintenance and differentiation, this article summarizes the functions of several classic developmental signaling pathways for lymph gland growth and patterning, highlighting the important roles of developmental signaling during lymph gland development as well as Drosophila larval hematopoiesis.
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Affiliation(s)
- Wenwen Lan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (W.L.); (S.L.)
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Sumin Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (W.L.); (S.L.)
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Long Zhao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (W.L.); (S.L.)
- Fisheries College, Ocean University of China, Qingdao 266003, China
- Correspondence: (L.Z.); (Y.S.)
| | - Ying Su
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (W.L.); (S.L.)
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- Correspondence: (L.Z.); (Y.S.)
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13
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Ramond E, Dudzic JP, Lemaitre B. Comparative RNA-Seq analyses of Drosophila plasmatocytes reveal gene specific signatures in response to clean injury and septic injury. PLoS One 2020; 15:e0235294. [PMID: 32598400 PMCID: PMC7323993 DOI: 10.1371/journal.pone.0235294] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/11/2020] [Indexed: 12/27/2022] Open
Abstract
Drosophila melanogaster's blood cells (hemocytes) play essential roles in wound healing and are involved in clearing microbial infections. Here, we report the transcriptional changes of larval plasmatocytes after clean injury or infection with the Gram-negative bacterium Escherichia coli or the Gram-positive bacterium Staphylococcus aureus compared to hemocytes recovered from unchallenged larvae via RNA-Sequencing. This study reveals 676 differentially expressed genes (DEGs) in hemocytes from clean injury samples compared to unchallenged samples, and 235 and 184 DEGs in E. coli and S. aureus samples respectively compared to clean injury samples. The clean injury samples showed enriched DEGs for immunity, clotting, cytoskeleton, cell migration, hemocyte differentiation, and indicated a metabolic reprogramming to aerobic glycolysis, a well-defined metabolic adaptation observed in mammalian macrophages. Microbial infections trigger significant transcription of immune genes, with significant differences between the E. coli and S. aureus samples suggesting that hemocytes have the ability to engage various programs upon infection. Collectively, our data bring new insights on Drosophila hemocyte function and open the route to post-genomic functional analysis of the cellular immune response.
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Affiliation(s)
- Elodie Ramond
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jan Paul Dudzic
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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14
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Creed TM, Baldeosingh R, Eberly CL, Schlee CS, Kim M, Cutler JA, Pandey A, Civin CI, Fossett NG, Kingsbury TJ. The PAX-SIX-EYA-DACH network modulates GATA-FOG function in fly hematopoiesis and human erythropoiesis. Development 2020; 147:dev.177022. [PMID: 31806659 DOI: 10.1242/dev.177022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 11/25/2019] [Indexed: 12/15/2022]
Abstract
The GATA and PAX-SIX-EYA-DACH transcriptional networks (PSEDNs) are essential for proper development across taxa. Here, we demonstrate novel PSEDN roles in vivo in Drosophila hematopoiesis and in human erythropoiesis in vitro Using Drosophila genetics, we show that PSEDN members function with GATA to block lamellocyte differentiation and maintain the prohemocyte pool. Overexpression of human SIX1 stimulated erythroid differentiation of human erythroleukemia TF1 cells and primary hematopoietic stem-progenitor cells. Conversely, SIX1 knockout impaired erythropoiesis in both cell types. SIX1 stimulation of erythropoiesis required GATA1, as SIX1 overexpression failed to drive erythroid phenotypes and gene expression patterns in GATA1 knockout cells. SIX1 can associate with GATA1 and stimulate GATA1-mediated gene transcription, suggesting that SIX1-GATA1 physical interactions contribute to the observed functional interactions. In addition, both fly and human SIX proteins regulated GATA protein levels. Collectively, our findings demonstrate that SIX proteins enhance GATA function at multiple levels, and reveal evolutionarily conserved cooperation between the GATA and PSEDN networks that may regulate developmental processes beyond hematopoiesis.
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Affiliation(s)
- T Michael Creed
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rajkumar Baldeosingh
- Center for Vascular and Inflammatory Diseases University of Maryland School of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India
| | - Christian L Eberly
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Caroline S Schlee
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - MinJung Kim
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jevon A Cutler
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Akhilesh Pandey
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Curt I Civin
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nancy G Fossett
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA .,Center for Vascular and Inflammatory Diseases University of Maryland School of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tami J Kingsbury
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA .,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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15
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Bailetti AA, Negrón-Piñeiro LJ, Dhruva V, Harsh S, Lu S, Bosula A, Bach EA. Enhancer of Polycomb and the Tip60 complex repress hematological tumor initiation by negatively regulating JAK/STAT pathway activity. Dis Model Mech 2019; 12:dmm.038679. [PMID: 31072879 PMCID: PMC6550037 DOI: 10.1242/dmm.038679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/18/2019] [Indexed: 12/13/2022] Open
Abstract
Myeloproliferative neoplasms (MPNs) are clonal hematopoietic disorders that cause excessive production of myeloid cells. Most MPN patients have a point mutation in JAK2 (JAK2V617F), which encodes a dominant-active kinase that constitutively triggers JAK/STAT signaling. In Drosophila, this pathway is simplified, with a single JAK, Hopscotch (Hop), and a single STAT transcription factor, Stat92E. The hopTumorous-lethal [hopTum] allele encodes a dominant-active kinase that induces sustained Stat92E activation. Like MPN patients, hopTum mutants have significantly more myeloid cells, which form invasive tumors. Through an unbiased genetic screen, we found that heterozygosity for Enhancer of Polycomb [E(Pc)], a component of the Tip60 lysine acetyltransferase complex (also known as KAT5 in humans), significantly increased tumor burden in hopTum animals. Hematopoietic depletion of E(Pc) or other Tip60 components in an otherwise wild-type background also induced blood cell tumors. The E(Pc) tumor phenotype was dependent on JAK/STAT activity, as concomitant depletion of hop or Stat92E inhibited tumor formation. Stat92E target genes were significantly upregulated in E(Pc)-mutant myeloid cells, indicating that loss of E(Pc) activates JAK/STAT signaling. Neither the hop nor Stat92E gene was upregulated upon hematopoietic E(Pc) depletion, suggesting that the regulation of the JAK/STAT pathway by E(Pc) is dependent on substrates other than histones. Indeed, E(Pc) depletion significantly increased expression of Hop protein in myeloid cells. This study indicates that E(Pc) works as a tumor suppressor by attenuating Hop protein expression and ultimately JAK/STAT signaling. Since loss-of-function mutations in the human homologs of E(Pc) and Tip60 are frequently observed in cancer, our work could lead to new treatments for MPN patients. This article has an associated First Person interview with the first author of the paper. Editor's choice: Using Drosophila as a low-complexity model for human myeloproliferative neoplasms, the authors identified a conserved mechanism by which the Tip60 lysine acetyltransferase acts as a tumor suppressor by repressing JAK protein expression in a histone-independent manner.
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Affiliation(s)
- Alessandro A Bailetti
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Lenny J Negrón-Piñeiro
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Vishal Dhruva
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Sneh Harsh
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Sean Lu
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Aisha Bosula
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Erika A Bach
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA .,Helen L. and Martin S. Kimmel Center for Stem Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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16
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Banerjee U, Girard JR, Goins LM, Spratford CM. Drosophila as a Genetic Model for Hematopoiesis. Genetics 2019; 211:367-417. [PMID: 30733377 PMCID: PMC6366919 DOI: 10.1534/genetics.118.300223] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/05/2018] [Indexed: 12/17/2022] Open
Abstract
In this FlyBook chapter, we present a survey of the current literature on the development of the hematopoietic system in Drosophila The Drosophila blood system consists entirely of cells that function in innate immunity, tissue integrity, wound healing, and various forms of stress response, and are therefore functionally similar to myeloid cells in mammals. The primary cell types are specialized for phagocytic, melanization, and encapsulation functions. As in mammalian systems, multiple sites of hematopoiesis are evident in Drosophila and the mechanisms involved in this process employ many of the same molecular strategies that exemplify blood development in humans. Drosophila blood progenitors respond to internal and external stress by coopting developmental pathways that involve both local and systemic signals. An important goal of these Drosophila studies is to develop the tools and mechanisms critical to further our understanding of human hematopoiesis during homeostasis and dysfunction.
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Affiliation(s)
- Utpal Banerjee
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
- Molecular Biology Institute, University of California, Los Angeles, California 90095
- Department of Biological Chemistry, University of California, Los Angeles, California 90095
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, California 90095
| | - Juliet R Girard
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
| | - Lauren M Goins
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
| | - Carrie M Spratford
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
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17
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Valanne S, Salminen TS, Järvelä-Stölting M, Vesala L, Rämet M. Immune-inducible non-coding RNA molecule lincRNA-IBIN connects immunity and metabolism in Drosophila melanogaster. PLoS Pathog 2019; 15:e1007504. [PMID: 30633769 PMCID: PMC6345493 DOI: 10.1371/journal.ppat.1007504] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 01/24/2019] [Accepted: 12/05/2018] [Indexed: 01/09/2023] Open
Abstract
Non-coding RNAs have important roles in regulating physiology, including immunity. Here, we performed transcriptome profiling of immune-responsive genes in Drosophila melanogaster during a Gram-positive bacterial infection, concentrating on long non-coding RNA (lncRNA) genes. The gene most highly induced by a Micrococcus luteus infection was CR44404, named Induced by Infection (lincRNA-IBIN). lincRNA-IBIN is induced by both Gram-positive and Gram-negative bacteria in Drosophila adults and parasitoid wasp Leptopilina boulardi in Drosophila larvae, as well as by the activation of the Toll or the Imd pathway in unchallenged flies. We show that upon infection, lincRNA-IBIN is expressed in the fat body, in hemocytes and in the gut, and its expression is regulated by NF-κB signaling and the chromatin modeling brahma complex. In the fat body, overexpression of lincRNA-IBIN affected the expression of Toll pathway -mediated genes. Notably, overexpression of lincRNA-IBIN in unchallenged flies elevated sugar levels in the hemolymph by enhancing the expression of genes important for glucose retrieval. These data show that lncRNA genes play a role in Drosophila immunity and indicate that lincRNA-IBIN acts as a link between innate immune responses and metabolism.
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Affiliation(s)
- Susanna Valanne
- Laboratory of Experimental Immunology, BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Tiina S. Salminen
- Laboratory of Experimental Immunology, BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Mirva Järvelä-Stölting
- Laboratory of Experimental Immunology, BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Laura Vesala
- Laboratory of Experimental Immunology, BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Mika Rämet
- Laboratory of Experimental Immunology, BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
- PEDEGO Research Unit, and Medical Research Center Oulu, University of Oulu, and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
- Department of Pediatrics, Tampere University Hospital, Tampere, Finland
- * E-mail:
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18
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Trivedi S, Starz-Gaiano M. Drosophila Jak/STAT Signaling: Regulation and Relevance in Human Cancer and Metastasis. Int J Mol Sci 2018; 19:ijms19124056. [PMID: 30558204 PMCID: PMC6320922 DOI: 10.3390/ijms19124056] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/08/2018] [Accepted: 12/11/2018] [Indexed: 12/26/2022] Open
Abstract
Over the past three-decades, Janus kinase (Jak) and signal transducer and activator of transcription (STAT) signaling has emerged as a paradigm to understand the involvement of signal transduction in development and disease pathology. At the molecular level, cytokines and interleukins steer Jak/STAT signaling to transcriptional regulation of target genes, which are involved in cell differentiation, migration, and proliferation. Jak/STAT signaling is involved in various types of blood cell disorders and cancers in humans, and its activation is associated with carcinomas that are more invasive or likely to become metastatic. Despite immense information regarding Jak/STAT regulation, the signaling network has numerous missing links, which is slowing the progress towards developing drug therapies. In mammals, many components act in this cascade, with substantial cross-talk with other signaling pathways. In Drosophila, there are fewer pathway components, which has enabled significant discoveries regarding well-conserved regulatory mechanisms. Work across species illustrates the relevance of these regulators in humans. In this review, we showcase fundamental Jak/STAT regulation mechanisms in blood cells, stem cells, and cell motility. We examine the functional relevance of key conserved regulators from Drosophila to human cancer stem cells and metastasis. Finally, we spotlight less characterized regulators of Drosophila Jak/STAT signaling, which stand as promising candidates to be investigated in cancer biology. These comparisons illustrate the value of using Drosophila as a model for uncovering the roles of Jak/STAT signaling and the molecular means by which the pathway is controlled.
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Affiliation(s)
- Sunny Trivedi
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Michelle Starz-Gaiano
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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19
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Baldeosingh R, Gao H, Wu X, Fossett N. Hedgehog signaling from the Posterior Signaling Center maintains U-shaped expression and a prohemocyte population in Drosophila. Dev Biol 2018; 441:132-145. [PMID: 29966604 PMCID: PMC6064674 DOI: 10.1016/j.ydbio.2018.06.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/15/2022]
Abstract
Hematopoietic progenitor choice between multipotency and differentiation is tightly regulated by intrinsic factors and extrinsic signals from the surrounding microenvironment. The Drosophila melanogaster hematopoietic lymph gland has emerged as a powerful tool to investigate mechanisms that regulate hematopoietic progenitor choice in vivo. The lymph gland contains progenitor cells, which share key characteristics with mammalian hematopoietic progenitors such as quiescence, multipotency and niche-dependence. The lymph gland is zonally arranged, with progenitors located in medullary zone, differentiating cells in the cortical zone, and the stem cell niche or Posterior Signaling Center (PSC) residing at the base of the medullary zone (MZ). This arrangement facilitates investigations into how signaling from the microenvironment controls progenitor choice. The Drosophila Friend of GATA transcriptional regulator, U-shaped, is a conserved hematopoietic regulator. To identify additional novel intrinsic and extrinsic regulators that interface with U-shaped to control hematopoiesis, we conducted an in vivo screen for factors that genetically interact with u-shaped. Smoothened, a downstream effector of Hedgehog signaling, was one of the factors identified in the screen. Here we report our studies that characterized the relationship between Smoothened and U-shaped. We showed that the PSC and Hedgehog signaling are required for U-shaped expression and that U-shaped is an important intrinsic progenitor regulator. These observations identify a potential link between the progenitor regulatory machinery and extrinsic signals from the PSC. Furthermore, we showed that both Hedgehog signaling and the PSC are required to maintain a subpopulation of progenitors. This led to a delineation of PSC-dependent versus PSC-independent progenitors and provided further evidence that the MZ progenitor population is heterogeneous. Overall, we have identified a connection between a conserved hematopoietic master regulator and a putative stem cell niche, which adds to our understanding of how signals from the microenvironment regulate progenitor multipotency.
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Affiliation(s)
- Rajkumar Baldeosingh
- Graduate Program in Life Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hongjuan Gao
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Xiaorong Wu
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nancy Fossett
- Graduate Program in Life Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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20
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Tokusumi Y, Tokusumi T, Schulz RA. Mechanical stress to Drosophila larvae stimulates a cellular immune response through the JAK/STAT signaling pathway. Biochem Biophys Res Commun 2018; 502:415-421. [DOI: 10.1016/j.bbrc.2018.05.192] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 11/27/2022]
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21
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Gyoergy A, Roblek M, Ratheesh A, Valoskova K, Belyaeva V, Wachner S, Matsubayashi Y, Sánchez-Sánchez BJ, Stramer B, Siekhaus DE. Tools Allowing Independent Visualization and Genetic Manipulation of Drosophila melanogaster Macrophages and Surrounding Tissues. G3 (BETHESDA, MD.) 2018; 8:845-857. [PMID: 29321168 PMCID: PMC5844306 DOI: 10.1534/g3.117.300452] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 12/31/2017] [Indexed: 12/19/2022]
Abstract
Drosophila melanogaster plasmatocytes, the phagocytic cells among hemocytes, are essential for immune responses, but also play key roles from early development to death through their interactions with other cell types. They regulate homeostasis and signaling during development, stem cell proliferation, metabolism, cancer, wound responses, and aging, displaying intriguing molecular and functional conservation with vertebrate macrophages. Given the relative ease of genetics in Drosophila compared to vertebrates, tools permitting visualization and genetic manipulation of plasmatocytes and surrounding tissues independently at all stages would greatly aid a fuller understanding of these processes, but are lacking. Here, we describe a comprehensive set of transgenic lines that allow this. These include extremely brightly fluorescing mCherry-based lines that allow GAL4-independent visualization of plasmatocyte nuclei, the cytoplasm, or the actin cytoskeleton from embryonic stage 8 through adulthood in both live and fixed samples even as heterozygotes, greatly facilitating screening. These lines allow live visualization and tracking of embryonic plasmatocytes, as well as larval plasmatocytes residing at the body wall or flowing with the surrounding hemolymph. With confocal imaging, interactions of plasmatocytes and inner tissues can be seen in live or fixed embryos, larvae, and adults. They permit efficient GAL4-independent Fluorescence-Activated Cell Sorting (FACS) analysis/sorting of plasmatocytes throughout life. To facilitate genetic studies of reciprocal signaling, we have also made a plasmatocyte-expressing QF2 line that, in combination with extant GAL4 drivers, allows independent genetic manipulation of both plasmatocytes and surrounding tissues, and GAL80 lines that block GAL4 drivers from affecting plasmatocytes, all of which function from the early embryo to the adult.
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Affiliation(s)
- Attila Gyoergy
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Marko Roblek
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Aparna Ratheesh
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Katarina Valoskova
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Vera Belyaeva
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Stephanie Wachner
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Yutaka Matsubayashi
- Randall Division of Cell and Molecular Biophysics, King's College London, SE1 1UL, United Kingdom
| | - Besaiz J Sánchez-Sánchez
- Randall Division of Cell and Molecular Biophysics, King's College London, SE1 1UL, United Kingdom
| | - Brian Stramer
- Randall Division of Cell and Molecular Biophysics, King's College London, SE1 1UL, United Kingdom
| | - Daria E Siekhaus
- The Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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22
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The human Smoothened inhibitor PF-04449913 induces exit from quiescence and loss of multipotent Drosophila hematopoietic progenitor cells. Oncotarget 2018; 7:55313-55327. [PMID: 27486815 PMCID: PMC5342419 DOI: 10.18632/oncotarget.10879] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/26/2016] [Indexed: 11/25/2022] Open
Abstract
The efficient treatment of hematological malignancies as Acute Myeloid Leukemia, myelofibrosis and Chronic Myeloid Leukemia, requires the elimination of cancer-initiating cells and the prevention of disease relapse through targeting pathways that stimulate generation and maintenance of these cells. In mammals, inhibition of Smoothened, the key mediator of the Hedgehog signaling pathway, reduces Chronic Myeloid Leukemia progression and propagation. These findings make Smo a candidate target to inhibit maintenance of leukemia-initiating cells. In Drosophila melanogaster the same pathway maintains the hematopoietic precursor cells of the lymph gland, the hematopoietic organ that develops in the larva. Using Drosophila as an in vivo model, we investigated the mode of action of PF-04449913, a small-molecule inhibitor of the human Smo protein. Drosophila larvae fed with PF-04449913 showed traits of altered hematopoietic homeostasis. These include the development of melanotic nodules, increase of circulating hemocytes, the size increase of the lymph gland and accelerated differentiation of blood cells likely due to the exit of multi-potent precursors from quiescence. Importantly, the Smo inhibition can lead to the complete loss of hematopoietic precursors. We conclude that PF-04449913 inhibits Drosophila Smo blocking the Hh signaling pathway and causing the loss of hematopoietic precursor cells. Interestingly, this is the effect expected in patients treated with PF-04449913: number decrease of cancer initiating cells in the bone marrow to reduce the risk of leukemia relapse. Altogether our results indicate that Drosophila comprises a model system for the in vivo study of molecules that target evolutionary conserved pathways implicated in human hematological malignancies.
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A Genetic Screen Reveals an Unexpected Role for Yorkie Signaling in JAK/STAT-Dependent Hematopoietic Malignancies in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2017; 7:2427-2438. [PMID: 28620086 PMCID: PMC5555452 DOI: 10.1534/g3.117.044172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A gain-of-function mutation in the tyrosine kinase JAK2 (JAK2V617F) causes human myeloproliferative neoplasms (MPNs). These patients present with high numbers of myeloid lineage cells and have numerous complications. Since current MPN therapies are not curative, there is a need to find new regulators and targets of Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling that may represent additional clinical interventions . Drosophila melanogaster offers a low complexity model to study MPNs as JAK/STAT signaling is simplified with only one JAK [Hopscotch (Hop)] and one STAT (Stat92E). hopTumorous-lethal(Tum-l) is a gain-of-function mutation that causes dramatic expansion of myeloid cells, which then form lethal melanotic tumors. Through an F1 deficiency (Df) screen, we identified 11 suppressors and 35 enhancers of melanotic tumors in hopTum-l animals. Dfs that uncover the Hippo (Hpo) pathway genes expanded (ex) and warts (wts) strongly enhanced the hopTum-l tumor burden, as did mutations in ex, wts, and other Hpo pathway genes. Target genes of the Hpo pathway effector Yorkie (Yki) were significantly upregulated in hopTum-l blood cells, indicating that Yki signaling was increased. Ectopic hematopoietic activation of Yki in otherwise wild-type animals increased hemocyte proliferation but did not induce melanotic tumors. However, hematopoietic depletion of Yki significantly reduced the hopTum-l tumor burden, demonstrating that Yki is required for melanotic tumors in this background. These results support a model in which elevated Yki signaling increases the number of hemocytes, which become melanotic tumors as a result of elevated JAK/STAT signaling.
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Screening and Analysis of Janelia FlyLight Project Enhancer-Gal4 Strains Identifies Multiple Gene Enhancers Active During Hematopoiesis in Normal and Wasp-Challenged Drosophila Larvae. G3-GENES GENOMES GENETICS 2017; 7:437-448. [PMID: 27913635 PMCID: PMC5295592 DOI: 10.1534/g3.116.034439] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A GFP expression screen has been conducted on >1000 Janelia FlyLight Project enhancer-Gal4 lines to identify transcriptional enhancers active in the larval hematopoietic system. A total of 190 enhancers associated with 87 distinct genes showed activity in cells of the third instar larval lymph gland and hemolymph. That is, gene enhancers were active in cells of the lymph gland posterior signaling center (PSC), medullary zone (MZ), and/or cortical zone (CZ), while certain of the transcriptional control regions were active in circulating hemocytes. Phenotypic analyses were undertaken on 81 of these hematopoietic-expressed genes, with nine genes characterized in detail as to gain- and loss-of-function phenotypes in larval hematopoietic tissues and blood cells. These studies demonstrated the functional requirement of the cut gene for proper PSC niche formation, the hairy, Btk29A, and E2F1 genes for blood cell progenitor production in the MZ domain, and the longitudinals lacking, dFOXO, kayak, cap-n-collar, and delilah genes for lamellocyte induction and/or differentiation in response to parasitic wasp challenge and infestation of larvae. Together, these findings contribute substantial information to our knowledge of genes expressed during the larval stage of Drosophila hematopoiesis and newly identify multiple genes required for this developmental process.
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Letourneau M, Lapraz F, Sharma A, Vanzo N, Waltzer L, Crozatier M. Drosophila hematopoiesis under normal conditions and in response to immune stress. FEBS Lett 2016; 590:4034-4051. [PMID: 27455465 DOI: 10.1002/1873-3468.12327] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 07/07/2016] [Accepted: 07/21/2016] [Indexed: 12/12/2022]
Abstract
The emergence of hematopoietic progenitors and their differentiation into various highly specialized blood cell types constitute a finely tuned process. Unveiling the genetic cascades that control blood cell progenitor fate and understanding how they are modulated in response to environmental changes are two major challenges in the field of hematopoiesis. In the last 20 years, many studies have established important functional analogies between blood cell development in vertebrates and in the fruit fly, Drosophila melanogaster. Thereby, Drosophila has emerged as a powerful genetic model for studying mechanisms that control hematopoiesis during normal development or in pathological situations. Moreover, recent advances in Drosophila have highlighted how intricate cell communication networks and microenvironmental cues regulate blood cell homeostasis. They have also revealed the striking plasticity of Drosophila mature blood cells and the presence of different sites of hematopoiesis in the larva. This review provides an overview of Drosophila hematopoiesis during development and summarizes our current knowledge on the molecular processes controlling larval hematopoiesis, both under normal conditions and in response to an immune challenge, such as wasp parasitism.
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Affiliation(s)
- Manon Letourneau
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France
| | - Francois Lapraz
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France
| | - Anurag Sharma
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France.,Department of Biomedical Sciences, NU Centre for Science Education & Research, Nitte University, Mangalore-18, India
| | - Nathalie Vanzo
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France
| | - Lucas Waltzer
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France
| | - Michèle Crozatier
- Centre de Biologie du Développement, UMR 5547 CNRS/Université Toulouse III and Centre de Biologie Intégrative, Toulouse Cedex 9, France
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Schmid MR, Anderl I, Vo HTM, Valanne S, Yang H, Kronhamn J, Rämet M, Rusten TE, Hultmark D. Genetic Screen in Drosophila Larvae Links ird1 Function to Toll Signaling in the Fat Body and Hemocyte Motility. PLoS One 2016; 11:e0159473. [PMID: 27467079 PMCID: PMC4965076 DOI: 10.1371/journal.pone.0159473] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 06/05/2016] [Indexed: 12/26/2022] Open
Abstract
To understand how Toll signaling controls the activation of a cellular immune response in Drosophila blood cells (hemocytes), we carried out a genetic modifier screen, looking for deletions that suppress or enhance the mobilization of sessile hemocytes by the gain-of-function mutation Toll10b (Tl10b). Here we describe the results from chromosome arm 3R, where five regions strongly suppressed this phenotype. We identified the specific genes immune response deficient 1 (ird1), headcase (hdc) and possibly Rab23 as suppressors, and we studied the role of ird1 in more detail. An ird1 null mutant and a mutant that truncates the N-terminal kinase domain of the encoded Ird1 protein affected the Tl10b phenotype, unlike mutations that affect the C-terminal part of the protein. The ird1 null mutant suppressed mobilization of sessile hemocytes, but enhanced other Tl10b hemocyte phenotypes, like the formation of melanotic nodules and the increased number of circulating hemocytes. ird1 mutants also had blood cell phenotypes on their own. They lacked crystal cells and showed aberrant formation of lamellocytes. ird1 mutant plasmatocytes had a reduced ability to spread on an artificial substrate by forming protrusions, which may explain why they did not go into circulation in response to Toll signaling. The effect of the ird1 mutation depended mainly on ird1 expression in hemocytes, but ird1-dependent effects in other tissues may contribute. Specifically, the Toll receptor was translocated from the cell membrane to intracellular vesicles in the fat body of the ird1 mutant, and Toll signaling was activated in that tissue, partially explaining the Tl10b-like phenotype. As ird1 is otherwise known to control vesicular transport, we conclude that the vesicular transport system may be of particular importance during an immune response.
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Affiliation(s)
| | - Ines Anderl
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- BioMediTech, University of Tampere, Tampere, Finland
| | - Hoa T. M. Vo
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Hairu Yang
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Jesper Kronhamn
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Mika Rämet
- BioMediTech, University of Tampere, Tampere, Finland
- PEDEGO Research Center, and Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Tor Erik Rusten
- Department of Molecular Cell Biology, Oslo University Hospital, Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway
| | - Dan Hultmark
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- BioMediTech, University of Tampere, Tampere, Finland
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Anderl I, Vesala L, Ihalainen TO, Vanha-aho LM, Andó I, Rämet M, Hultmark D. Transdifferentiation and Proliferation in Two Distinct Hemocyte Lineages in Drosophila melanogaster Larvae after Wasp Infection. PLoS Pathog 2016; 12:e1005746. [PMID: 27414410 PMCID: PMC4945071 DOI: 10.1371/journal.ppat.1005746] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/16/2016] [Indexed: 12/18/2022] Open
Abstract
Cellular immune responses require the generation and recruitment of diverse blood cell types that recognize and kill pathogens. In Drosophila melanogaster larvae, immune-inducible lamellocytes participate in recognizing and killing parasitoid wasp eggs. However, the sequence of events required for lamellocyte generation remains controversial. To study the cellular immune system, we developed a flow cytometry approach using in vivo reporters for lamellocytes as well as for plasmatocytes, the main hemocyte type in healthy larvae. We found that two different blood cell lineages, the plasmatocyte and lamellocyte lineages, contribute to the generation of lamellocytes in a demand-adapted hematopoietic process. Plasmatocytes transdifferentiate into lamellocyte-like cells in situ directly on the wasp egg. In parallel, a novel population of infection-induced cells, which we named lamelloblasts, appears in the circulation. Lamelloblasts proliferate vigorously and develop into the major class of circulating lamellocytes. Our data indicate that lamellocyte differentiation upon wasp parasitism is a plastic and dynamic process. Flow cytometry with in vivo hemocyte reporters can be used to study this phenomenon in detail.
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Affiliation(s)
- Ines Anderl
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Laura Vesala
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
| | - Teemu O. Ihalainen
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
| | - Leena-Maija Vanha-aho
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
| | - István Andó
- Institute of Genetics Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Mika Rämet
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
- PEDEGO Research Unit, and Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Dan Hultmark
- Institute of Biosciences and Medical Technology, BioMediTech, University of Tampere, Tampere, Finland
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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The Friend of GATA Transcriptional Co-Regulator, U-Shaped, Is a Downstream Antagonist of Dorsal-Driven Prohemocyte Differentiation in Drosophila. PLoS One 2016; 11:e0155372. [PMID: 27163255 PMCID: PMC4862636 DOI: 10.1371/journal.pone.0155372] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 04/27/2016] [Indexed: 12/11/2022] Open
Abstract
Recent studies suggest that mammalian hematopoietic stem and progenitor cells (HSPCs) respond directly to infection and inflammatory signaling. These signaling pathways also regulate HSPCs during steady-state conditions (absence of infection), and dysregulation may lead to cancer or age-related loss of progenitor repopulation capacity. Toll-like receptors (TLRs) are a major class of pathogen recognition receptors, and are expressed on the surface of immune effector cells and HSPCs. TLR/NF-κB activation promotes HSPCs differentiation; however, the mechanisms by which this signaling pathway alters the intrinsic transcriptional landscape are not well understood. Although Drosophila prohemocytes are the functional equivalent of mammalian HSPCs, a prohemocyte-specific function for Toll signaling has not been reported. Using Drosophila transgenics, we identified prohemocyte-specific roles for Toll pathway members, Dorsal and Cactus. We showed that Dorsal is required to limit the size of the progenitor pool. Additionally, we showed that activation of Toll signaling in prohemocytes drives differentiation in a manner that is analogous to TLR/NF-κB-driven HSPC differentiation. This was accomplished by showing that over-expression of Dorsal, or knockdown of Cactus, promotes differentiation. We also investigated whether Dorsal and Cactus control prohemocyte differentiation by regulating a key intrinsic prohemocyte factor, U-shaped (Ush), which is known to promote multipotency and block differentiation. We showed that Dorsal repressed Ush expression levels to promote differentiation, whereas Cactus maintained Ush levels to block differentiation. Additionally, we showed that another Toll antagonist, Lesswright, also maintained the level of Ush to block differentiation and promote proliferative quiescence. Collectively, these results identify a novel role for Ush as a downstream target of Toll signaling.
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Oyallon J, Vanzo N, Krzemień J, Morin-Poulard I, Vincent A, Crozatier M. Two Independent Functions of Collier/Early B Cell Factor in the Control of Drosophila Blood Cell Homeostasis. PLoS One 2016; 11:e0148978. [PMID: 26866694 PMCID: PMC4750865 DOI: 10.1371/journal.pone.0148978] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/26/2016] [Indexed: 11/18/2022] Open
Abstract
Blood cell production in the Drosophila hematopoietic organ, the lymph gland, is controlled by intrinsic factors and extrinsic signals. Initial analysis of Collier/Early B Cell Factor function in the lymph gland revealed the role of the Posterior Signaling Center (PSC) in mounting a dedicated cellular immune response to wasp parasitism. Further, premature blood cell differentiation when PSC specification or signaling was impaired, led to assigning the PSC a role equivalent to the vertebrate hematopoietic niche. We report here that Collier is expressed in a core population of lymph gland progenitors and cell autonomously maintains this population. The PSC contributes to lymph gland homeostasis by regulating blood cell differentiation, rather than by maintaining core progenitors. In addition to PSC signaling, switching off Collier expression in progenitors is required for efficient immune response to parasitism. Our data show that two independent sites of Collier/Early B Cell Factor expression, hematopoietic progenitors and the PSC, achieve control of hematopoiesis.
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Affiliation(s)
- Justine Oyallon
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
| | - Nathalie Vanzo
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
| | - Joanna Krzemień
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
| | - Ismaël Morin-Poulard
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
| | - Alain Vincent
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
| | - Michèle Crozatier
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), University Paul Sabatier (UPS), CNRS, 118 Route de Narbonne 31062 Toulouse cedex 09, France
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Functional Conservation of the Glide/Gcm Regulatory Network Controlling Glia, Hemocyte, and Tendon Cell Differentiation in Drosophila. Genetics 2015; 202:191-219. [PMID: 26567182 PMCID: PMC4701085 DOI: 10.1534/genetics.115.182154] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/03/2015] [Indexed: 12/21/2022] Open
Abstract
High-throughput screens allow us to understand how transcription factors trigger developmental processes, including cell specification. A major challenge is identification of their binding sites because feedback loops and homeostatic interactions may mask the direct impact of those factors in transcriptome analyses. Moreover, this approach dissects the downstream signaling cascades and facilitates identification of conserved transcriptional programs. Here we show the results and the validation of a DNA adenine methyltransferase identification (DamID) genome-wide screen that identifies the direct targets of Glide/Gcm, a potent transcription factor that controls glia, hemocyte, and tendon cell differentiation in Drosophila. The screen identifies many genes that had not been previously associated with Glide/Gcm and highlights three major signaling pathways interacting with Glide/Gcm: Notch, Hedgehog, and JAK/STAT, which all involve feedback loops. Furthermore, the screen identifies effector molecules that are necessary for cell-cell interactions during late developmental processes and/or in ontogeny. Typically, immunoglobulin (Ig) domain-containing proteins control cell adhesion and axonal navigation. This shows that early and transiently expressed fate determinants not only control other transcription factors that, in turn, implement a specific developmental program but also directly affect late developmental events and cell function. Finally, while the mammalian genome contains two orthologous Gcm genes, their function has been demonstrated in vertebrate-specific tissues, placenta, and parathyroid glands, begging questions on the evolutionary conservation of the Gcm cascade in higher organisms. Here we provide the first evidence for the conservation of Gcm direct targets in humans. In sum, this work uncovers novel aspects of cell specification and sets the basis for further understanding of the role of conserved Gcm gene regulatory cascades.
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Van De Bor V, Zimniak G, Papone L, Cerezo D, Malbouyres M, Juan T, Ruggiero F, Noselli S. Companion Blood Cells Control Ovarian Stem Cell Niche Microenvironment and Homeostasis. Cell Rep 2015; 13:546-560. [PMID: 26456819 DOI: 10.1016/j.celrep.2015.09.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/27/2015] [Accepted: 09/01/2015] [Indexed: 01/23/2023] Open
Abstract
The extracellular matrix plays an essential role for stem cell differentiation and niche homeostasis. Yet, the origin and mechanism of assembly of the stem cell niche microenvironment remain poorly characterized. Here, we uncover an association between the niche and blood cells, leading to the formation of the Drosophila ovarian germline stem cell niche basement membrane. We identify a distinct pool of plasmatocytes tightly associated with the developing ovaries from larval stages onward. Expressing tagged collagen IV tissue specifically, we show that the germline stem cell niche basement membrane is produced by these "companion plasmatocytes" in the larval gonad and persists throughout adulthood, including the reproductive period. Eliminating companion plasmatocytes or specifically blocking their collagen IV expression during larval stages results in abnormal adult niches with excess stem cells, a phenotype due to aberrant BMP signaling. Thus, local interactions between the niche and blood cells during gonad development are essential for adult germline stem cell niche microenvironment assembly and homeostasis.
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Affiliation(s)
- Véronique Van De Bor
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France.
| | - Geordie Zimniak
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France
| | - Lise Papone
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France
| | - Delphine Cerezo
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France
| | - Marilyne Malbouyres
- Institut de Génomique Fonctionnelle de Lyon-ENS de Lyon, CNRS UMR 5242, INRA USC 1370, 46, allée d'Italie, 69364 Lyon Cedex 07, France
| | - Thomas Juan
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France
| | - Florence Ruggiero
- Institut de Génomique Fonctionnelle de Lyon-ENS de Lyon, CNRS UMR 5242, INRA USC 1370, 46, allée d'Italie, 69364 Lyon Cedex 07, France
| | - Stéphane Noselli
- University of Nice Sophia Antipolis, Institut de Biologie Valrose, iBV, 06108 Nice, France; CNRS, Institut de Biologie Valrose, iBV, UMR 7277, 06108 Nice, France; INSERM, Institut de Biologie Valrose, iBV, U1091, 06108 Nice, France.
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The EBF transcription factor Collier directly promotes Drosophila blood cell progenitor maintenance independently of the niche. Proc Natl Acad Sci U S A 2015; 112:9052-7. [PMID: 26150488 DOI: 10.1073/pnas.1423967112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The maintenance of stem or progenitor cell fate relies on intrinsic factors as well as local cues from the cellular microenvironment and systemic signaling. In the lymph gland, an hematopoietic organ in Drosophila larva, a group of cells called the Posterior Signaling Centre (PSC), whose specification depends on the EBF transcription factor Collier (Col) and the HOX factor Antennapedia (Antp), has been proposed to form a niche required to maintain the pool of hematopoietic progenitors (prohemocytes). In contrast with this model, we show here that genetic ablation of the PSC does not cause an increase in blood cell differentiation or a loss of blood cell progenitors. Furthermore, although both col and Antp mutant larvae are devoid of PSC, the massive prohemocyte differentiation observed in col mutant is not phenocopied in Antp mutant. Interestingly, beside its expression in the PSC, Col is also expressed at low levels in prohemocytes and we show that this expression persists in PSC-ablated and Antp mutant larvae. Moreover, targeted knockdown and rescue experiments indicate that Col expression is required in the prohemocytes to prevent their differentiation. Together, our findings show that the PSC is dispensable for blood cell progenitor maintenance and reveal the key role of the conserved transcription factor Col as an intrinsic regulator of hematopoietic progenitor fate.
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Tokusumi T, Tokusumi Y, Hopkins DW, Schulz RA. Bag of Marbles controls the size and organization of the Drosophila hematopoietic niche through interactions with the Insulin-like growth factor pathway and Retinoblastoma-family protein. Development 2015; 142:2261-7. [PMID: 26041767 DOI: 10.1242/dev.121798] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/20/2015] [Indexed: 01/01/2023]
Abstract
Bag of Marbles (Bam) is known to function as a positive regulator of hematopoietic progenitor maintenance in the lymph gland blood cell-forming organ during Drosophila hematopoiesis. Here, we demonstrate a key function for Bam in cells of the lymph gland posterior signaling center (PSC), a cellular domain proven to function as a hematopoietic niche. Bam is expressed in PSC cells, and gene loss-of-function results in PSC overgrowth and disorganization, indicating that Bam plays a crucial role in controlling the proper development of the niche. It was previously shown that Insulin receptor (InR) pathway signaling is essential for proper PSC cell proliferation. We analyzed PSC cell number in lymph glands double-mutant for bam and InR pathway genes, and observed that bam genetically interacts with pathway members in the formation of a normal PSC. The elF4A protein is a translation factor downstream of InR pathway signaling, and functional knockdown of this crucial regulator rescued the bam PSC overgrowth phenotype, further supporting the cooperative function of Bam with InR pathway members. Additionally, we documented that the Retinoblastoma-family protein (Rbf), a proven regulator of cell proliferation, was present in cells of the PSC, with a bam function-dependent expression. By contrast, perturbation of Decapentaplegic or Wingless signaling failed to affect Rbf niche cell expression. Together, these findings indicate that InR pathway-Bam-Rbf functional interactions represent a newly identified means to regulate the correct size and organization of the PSC hematopoietic niche.
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Affiliation(s)
- Tsuyoshi Tokusumi
- Department of Biological Sciences, University of Notre Dame, 147 Galvin Life Science Building, Notre Dame, IN 46556, USA
| | - Yumiko Tokusumi
- Department of Biological Sciences, University of Notre Dame, 147 Galvin Life Science Building, Notre Dame, IN 46556, USA
| | - Dawn W Hopkins
- Department of Biological Sciences, University of Notre Dame, 147 Galvin Life Science Building, Notre Dame, IN 46556, USA
| | - Robert A Schulz
- Department of Biological Sciences, University of Notre Dame, 147 Galvin Life Science Building, Notre Dame, IN 46556, USA
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Vanha-aho LM, Anderl I, Vesala L, Hultmark D, Valanne S, Rämet M. Edin Expression in the Fat Body Is Required in the Defense Against Parasitic Wasps in Drosophila melanogaster. PLoS Pathog 2015; 11:e1004895. [PMID: 25965263 PMCID: PMC4429011 DOI: 10.1371/journal.ppat.1004895] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 04/19/2015] [Indexed: 12/17/2022] Open
Abstract
The cellular immune response against parasitoid wasps in Drosophila involves the activation, mobilization, proliferation and differentiation of different blood cell types. Here, we have assessed the role of Edin (elevated during infection) in the immune response against the parasitoid wasp Leptopilina boulardi in Drosophila melanogaster larvae. The expression of edin was induced within hours after a wasp infection in larval fat bodies. Using tissue-specific RNAi, we show that Edin is an important determinant of the encapsulation response. Although edin expression in the fat body was required for the larvae to mount a normal encapsulation response, it was dispensable in hemocytes. Edin expression in the fat body was not required for lamellocyte differentiation, but it was needed for the increase in plasmatocyte numbers and for the release of sessile hemocytes into the hemolymph. We conclude that edin expression in the fat body affects the outcome of a wasp infection by regulating the increase of plasmatocyte numbers and the mobilization of sessile hemocytes in Drosophila larvae. The events leading to a successful encapsulation of parasitoid wasp eggs in the larvae of the fruit fly Drosophila melanogaster are insufficiently understood. The formation of a capsule seals off the wasp egg, and this process is often functionally compared to the formation of granulomas in vertebrates. Like granuloma formation in humans, the encapsulation process in fruit flies requires the activation, mobilization, proliferation and differentiation of different blood cell types. Here, we have studied the role of Edin (elevated during infection) in the immune defense against the parasitoid wasp Leptopilina boulardi in Drosophila larvae. We demonstrate that edin expression in the fat body (an immune-responsive organ in Drosophila functionally resembling the mammalian liver) is required for a normal defense against wasp eggs. Edin is required for the release of blood cells from larval tissues and for the subsequent increase in circulating blood cell numbers. Our results provide new knowledge of how the encapsulation process is regulated in Drosophila, and how blood cells are activated upon wasp parasitism. Understanding of the encapsulation process in invertebrates may eventually lead to a better knowledge of the pathophysiology of granuloma formation in human diseases, such as tuberculosis.
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Affiliation(s)
- Leena-Maija Vanha-aho
- Laboratory of Experimental Immunology, BioMediTech, University of Tampere, Tampere, Finland
| | - Ines Anderl
- Laboratory of Genetic Immunology, BioMediTech, University of Tampere, Tampere, Finland
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Laura Vesala
- Laboratory of Genetic Immunology, BioMediTech, University of Tampere, Tampere, Finland
| | - Dan Hultmark
- Laboratory of Genetic Immunology, BioMediTech, University of Tampere, Tampere, Finland
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Susanna Valanne
- Laboratory of Experimental Immunology, BioMediTech, University of Tampere, Tampere, Finland
| | - Mika Rämet
- Laboratory of Experimental Immunology, BioMediTech, University of Tampere, Tampere, Finland
- Department of Pediatrics, Tampere University Hospital, Tampere, Finland
- PEDEGO Research Center, and Medical Research Center Oulu, University of Oulu and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
- * E-mail:
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Basement membrane and cell integrity of self-tissues in maintaining Drosophila immunological tolerance. PLoS Genet 2014; 10:e1004683. [PMID: 25329560 PMCID: PMC4199487 DOI: 10.1371/journal.pgen.1004683] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 08/18/2014] [Indexed: 12/20/2022] Open
Abstract
The mechanism underlying immune system recognition of different types of pathogens has been extensively studied over the past few decades; however, the mechanism by which healthy self-tissue evades an attack by its own immune system is less well-understood. Here, we established an autoimmune model of melanotic mass formation in Drosophila by genetically disrupting the basement membrane. We found that the basement membrane endows otherwise susceptible target tissues with self-tolerance that prevents autoimmunity, and further demonstrated that laminin is a key component for both structural maintenance and the self-tolerance checkpoint function of the basement membrane. Moreover, we found that cell integrity, as determined by cell-cell interaction and apicobasal polarity, functions as a second discrete checkpoint. Target tissues became vulnerable to blood cell encapsulation and subsequent melanization only after loss of both the basement membrane and cell integrity.
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Lam V, Tokusumi T, Tokusumi Y, Schulz RA. bantam miRNA is important for Drosophila blood cell homeostasis and a regulator of proliferation in the hematopoietic progenitor niche. Biochem Biophys Res Commun 2014; 453:467-72. [PMID: 25280996 DOI: 10.1016/j.bbrc.2014.09.109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 09/24/2014] [Indexed: 12/19/2022]
Abstract
The Drosophila hematopoietic system is utilized in this study to gain novel insights into the process of growth control of the hematopoietic progenitor niche in blood development. The niche microenvironment is an essential component controlling the balance between progenitor populations and differentiated, mature blood cells and has been shown to lead to hematopoietic malignancies in humans when misregulated. MicroRNAs are one class of regulators associated with blood malignancies; however, there remains a relative paucity of information about the role of miRNAs in the niche. Here we demonstrate that bantam miRNA is endogenously active in the Drosophila hematopoietic progenitor niche, the posterior signaling center (PSC), and functions in the primary hematopoietic organ, the lymph gland, as a positive regulator of growth. Loss of bantam leads to a significant reduction in the PSC and overall lymph gland size, as well as a loss of the progenitor population and correlative premature differentiation of mature hemocytes. Interestingly, in addition to being essential for proper lymph gland development, we have determined bantam to be a novel upstream component of the insulin signaling cascade in the PSC and have unveiled dMyc as one factor central to bantam activity. These important findings identify bantam as a new hematopoietic regulator, place it in an evolutionarily conserved signaling pathway, present one way in which it is regulated, and provide a mechanism through which it facilitates cellular proliferation in the hematopoietic niche.
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Affiliation(s)
- Victoria Lam
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Tsuyoshi Tokusumi
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Yumiko Tokusumi
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Robert A Schulz
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
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Control of Drosophila blood cell activation via Toll signaling in the fat body. PLoS One 2014; 9:e102568. [PMID: 25102059 PMCID: PMC4125153 DOI: 10.1371/journal.pone.0102568] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/20/2014] [Indexed: 12/23/2022] Open
Abstract
The Toll signaling pathway, first discovered in Drosophila, has a well-established role in immune responses in insects as well as in mammals. In Drosophila, the Toll-dependent induction of antimicrobial peptide production has been intensely studied as a model for innate immune responses in general. Besides this humoral immune response, Toll signaling is also known to activate blood cells in a reaction that is similar to the cellular immune response to parasite infections, but the mechanisms of this response are poorly understood. Here we have studied this response in detail, and found that Toll signaling in several different tissues can activate a cellular immune defense, and that this response does not require Toll signaling in the blood cells themselves. Like in the humoral immune response, we show that Toll signaling in the fat body (analogous to the liver in vertebrates) is of major importance in the Toll-dependent activation of blood cells. However, this Toll-dependent mechanism of blood cell activation contributes very little to the immune response against the parasitoid wasp, Leptopilina boulardi, probably because the wasp is able to suppress Toll induction. Other redundant pathways may be more important in the defense against this pathogen.
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38
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Amoyel M, Anderson AM, Bach EA. JAK/STAT pathway dysregulation in tumors: a Drosophila perspective. Semin Cell Dev Biol 2014; 28:96-103. [PMID: 24685611 PMCID: PMC4037387 DOI: 10.1016/j.semcdb.2014.03.023] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/17/2014] [Accepted: 03/20/2014] [Indexed: 12/18/2022]
Abstract
Sustained activation of the JAK/STAT pathway is causal to human cancers. This pathway is less complex in Drosophila, and its dysregulation has been linked to several tumor models in this organism. Here, we discuss models of metastatic epithelial and hematopoietic tumors that are causally linked to dysregulation of JAK/STAT signaling in Drosophila. First, we focus on cancer models in imaginal discs where ectopic expression of the JAK/STAT pathway ligand Unpaired downstream of distinct tumor suppressors has emerged as an unexpected mediator of neoplastic transformation. We also discuss the collaboration between STAT and oncogenic Ras in epithelial transformation. Second, we examine hematopoietic tumors, where mutations that cause hyperactive JAK/STAT signaling are necessary and sufficient for "fly leukemia". We highlight the important contributions that genetic screens in Drosophila have made to understanding the JAK/STAT pathway, its developmental roles, and how its function is co-opted during tumorigenesis.
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Affiliation(s)
- Marc Amoyel
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, MSB 497B, New York, NY 10016, USA
| | - Abigail M Anderson
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, MSB 497B, New York, NY 10016, USA
| | - Erika A Bach
- The Helen L. and Martin S. Kimmel Center for Stem Cell Biology, New York University School of Medicine.
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Honti V, Csordás G, Kurucz É, Márkus R, Andó I. The cell-mediated immunity of Drosophila melanogaster: hemocyte lineages, immune compartments, microanatomy and regulation. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:47-56. [PMID: 23800719 DOI: 10.1016/j.dci.2013.06.005] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
In the animal kingdom, innate immunity is the first line of defense against invading pathogens. The dangers of microbial and parasitic attacks are countered by similar mechanisms, involving the prototypes of the cell-mediated immune responses, the phagocytosis and encapsulation. Work on Drosophila has played an important role in promoting an understanding of the basic mechanisms of phylogenetically conserved modules of innate immunity. The aim of this review is to survey the developments in the identification and functional definition of immune cell types and the immunological compartments of Drosophila melanogaster. We focus on the molecular and developmental aspects of the blood cell types and compartments, as well as the dynamics of blood cell development and the immune response. Further advances in the characterization of the innate immune mechanisms in Drosophila will provide basic clues to the understanding of the importance of the evolutionary conserved mechanisms of innate immune defenses in the animal kingdom.
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Affiliation(s)
- Viktor Honti
- Institute of Genetics Biological Research Centre of the Hungarian Academy of Sciences, P.O. Box 521, Szeged H-6701, Hungary
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40
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Knockdown of SCF(Skp2) function causes double-parked accumulation in the nucleus and DNA re-replication in Drosophila plasmatocytes. PLoS One 2013; 8:e79019. [PMID: 24205363 PMCID: PMC3812016 DOI: 10.1371/journal.pone.0079019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 09/18/2013] [Indexed: 12/25/2022] Open
Abstract
In Drosophila, circulating hemocytes are derived from the cephalic mesoderm during the embryonic wave of hematopoiesis. These cells are contributed to the larva and persist through metamorphosis into the adult. To analyze this population of hemocytes, we considered data from a previously published RNAi screen in the hematopoietic niche, which suggested several members of the SCF complex play a role in lymph gland development. eater-Gal4;UAS-GFP flies were crossed to UAS-RNAi lines to knockdown the function of all known SCF complex members in a plasmatocyte-specific fashion, in order to identify which members are novel regulators of plasmatocytes. This specific SCF complex contains five core members: Lin-19-like, SkpA, Skp2, Roc1a and complex activator Nedd8. The complex was identified by its very distinctive large cell phenotype. Furthermore, these large cells stained for anti-P1, a plasmatocyte-specific antibody. It was also noted that the DNA in these cells appeared to be over-replicated. Gamma-tubulin and DAPI staining suggest the cells are undergoing re-replication as they had multiple centrioles and excessive DNA content. Further experimentation determined enlarged cells were BrdU-positive indicating they have progressed through S-phase. To determine how these cells become enlarged and undergo re-replication, cell cycle proteins were analyzed by immunofluorescence. This analysis identified three proteins that had altered subcellular localization in these enlarged cells: Cyclin E, Geminin and Double-parked. Previous research has shown that Double-parked must be degraded to exit S-phase, otherwise the DNA will undergo re-replication. When Double-parked was titrated from the nucleus by an excess of its inhibitor, geminin, the enlarged cells and aberrant protein localization phenotypes were partially rescued. The data in this report suggests that the SCFSkp2 complex is necessary to ubiquitinate Double-parked during plasmatocyte cell division, ensuring proper cell cycle progression and the generation of a normal population of this essential blood cell type.
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41
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Gao H, Wu X, Fossett N. Drosophila E-cadherin functions in hematopoietic progenitors to maintain multipotency and block differentiation. PLoS One 2013; 8:e74684. [PMID: 24040319 PMCID: PMC3764055 DOI: 10.1371/journal.pone.0074684] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 08/07/2013] [Indexed: 01/12/2023] Open
Abstract
A fundamental question in stem cell biology concerns the regulatory strategies that control the choice between multipotency and differentiation. Drosophila blood progenitors or prohemocytes exhibit key stem cell characteristics, including multipotency, quiescence, and niche dependence. As a result, studies of Drosophila hematopoiesis have provided important insights into the molecular mechanisms that control these processes. Here, we show that E-cadherin is an important regulator of prohemocyte fate choice, maintaining prohemocyte multipotency and blocking differentiation. These functions are reminiscent of the role of E-cadherin in mammalian embryonic stem cells. We also show that mis-expression of E-cadherin in differentiating hemocytes disrupts the boundary between these cells and undifferentiated prohemocytes. Additionally, upregulation of E-cadherin in differentiating hemocytes increases the number of intermediate cell types expressing the prohemocyte marker, Patched. Furthermore, our studies indicate that the Drosophila GATA transcriptional co-factor, U-shaped, is required for E-cadherin expression. Consequently, E-cadherin is a downstream target of U-shaped in the maintenance of prohemocyte multipotency. In contrast, we showed that forced expression of the U-shaped GATA-binding partner, Serpent, repressed E-cadherin expression and promoted lamellocyte differentiation. Thus, U-shaped may maintain E-cadherin expression by blocking the inhibitory activity of Serpent. Collectively, these observations suggest that GATA:FOG complex formation regulates E-cadherin levels and, thereby, the choice between multipotency and differentiation. The work presented in this report further defines the molecular basis of prohemocyte cell fate choice, which will provide important insights into the mechanisms that govern stem cell biology.
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Affiliation(s)
- Hongjuan Gao
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Xiaorong Wu
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nancy Fossett
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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42
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Dragojlovic-Munther M, Martinez-Agosto JA. Extracellular matrix-modulated Heartless signaling in Drosophila blood progenitors regulates their differentiation via a Ras/ETS/FOG pathway and target of rapamycin function. Dev Biol 2013; 384:313-30. [PMID: 23603494 DOI: 10.1016/j.ydbio.2013.04.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 04/03/2013] [Accepted: 04/05/2013] [Indexed: 12/29/2022]
Abstract
Maintenance of hematopoietic progenitors ensures a continuous supply of blood cells during the lifespan of an organism. Thus, understanding the molecular basis for progenitor maintenance is a continued focus of investigation. A large pool of undifferentiated blood progenitors are maintained in the Drosophila hematopoietic organ, the larval lymph gland, by a complex network of signaling pathways that are mediated by niche-, progenitor-, or differentiated hemocyte-derived signals. In this study we examined the function of the Drosophila fibroblast growth factor receptor (FGFR), Heartless, a critical regulator of early lymph gland progenitor specification in the late embryo, during larval lymph gland hematopoiesis. Activation of Heartless signaling in hemocyte progenitors by its two ligands, Pyramus and Thisbe, is both required and sufficient to induce progenitor differentiation and formation of the plasmatocyte-rich lymph gland cortical zone. We identify two transcriptional regulators that function downstream of Heartless signaling in lymph gland progenitors, the ETS protein, Pointed, and the Friend-of-GATA (FOG) protein, U-shaped, which are required for this Heartless-induced differentiation response. Furthermore, cross-talk of Heartless and target of rapamycin signaling in hemocyte progenitors is required for lamellocyte differentiation downstream of Thisbe-mediated Heartless activation. Finally, we identify the Drosophila heparan sulfate proteoglycan, Trol, as a critical negative regulator of Heartless ligand signaling in the lymph gland, demonstrating that sequestration of differentiation signals by the extracellular matrix is a unique mechanism employed in blood progenitor maintenance that is of potential relevance to many other stem cell niches.
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43
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Terriente-Felix A, Li J, Collins S, Mulligan A, Reekie I, Bernard F, Krejci A, Bray S. Notch cooperates with Lozenge/Runx to lock haemocytes into a differentiation programme. Development 2013; 140:926-37. [PMID: 23325760 DOI: 10.1242/dev.086785] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The diverse functions of Notch signalling imply that it must elicit context-specific programmes of gene expression. With the aim of investigating how Notch drives cells to differentiate, we have used a genome-wide approach to identify direct Notch targets in Drosophila haemocytes (blood cells), where Notch promotes crystal cell differentiation. Many of the identified Notch-regulated enhancers contain Runx and GATA motifs, and we demonstrate that binding of the Runx protein Lozenge (Lz) is required for enhancers to be competent to respond to Notch. Functional studies of targets, such as klumpfuss (ERG/WT1 family) and pebbled/hindsight (RREB1 homologue), show that Notch acts both to prevent the cells adopting alternate cell fates and to promote morphological characteristics associated with crystal cell differentiation. Inappropriate activity of Klumpfuss perturbs the differentiation programme, resulting in melanotic tumours. Thus, by acting as a master regulator, Lz directs Notch to activate selectively a combination of target genes that correctly locks cells into the differentiation programme.
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Affiliation(s)
- Ana Terriente-Felix
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.
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44
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Chlon TM, Crispino JD. Combinatorial regulation of tissue specification by GATA and FOG factors. Development 2012; 139:3905-16. [PMID: 23048181 DOI: 10.1242/dev.080440] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The development of complex organisms requires the formation of diverse cell types from common stem and progenitor cells. GATA family transcriptional regulators and their dedicated co-factors, termed Friend of GATA (FOG) proteins, control cell fate and differentiation in multiple tissue types from Drosophila to man. FOGs can both facilitate and antagonize GATA factor transcriptional regulation depending on the factor, cell, and even the specific gene target. In this review, we highlight recent studies that have elucidated mechanisms by which FOGs regulate GATA factor function and discuss how these factors use these diverse modes of gene regulation to control cell lineage specification throughout metazoans.
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Affiliation(s)
- Timothy M Chlon
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
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45
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Gene regulatory networks controlling hematopoietic progenitor niche cell production and differentiation in the Drosophila lymph gland. PLoS One 2012; 7:e41604. [PMID: 22911822 PMCID: PMC3404040 DOI: 10.1371/journal.pone.0041604] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/21/2012] [Indexed: 02/08/2023] Open
Abstract
Hematopoiesis occurs in two phases in Drosophila, with the first completed during embryogenesis and the second accomplished during larval development. The lymph gland serves as the venue for the final hematopoietic program, with this larval tissue well-studied as to its cellular organization and genetic regulation. While the medullary zone contains stem-like hematopoietic progenitors, the posterior signaling center (PSC) functions as a niche microenvironment essential for controlling the decision between progenitor maintenance versus cellular differentiation. In this report, we utilize a PSC-specific GAL4 driver and UAS-gene RNAi strains, to selectively knockdown individual gene functions in PSC cells. We assessed the effect of abrogating the function of 820 genes as to their requirement for niche cell production and differentiation. 100 genes were shown to be essential for normal niche development, with various loci placed into sub-groups based on the functions of their encoded protein products and known genetic interactions. For members of three of these groups, we characterized loss- and gain-of-function phenotypes. Gene function knockdown of members of the BAP chromatin-remodeling complex resulted in niche cells that do not express the hedgehog (hh) gene and fail to differentiate filopodia believed important for Hh signaling from the niche to progenitors. Abrogating gene function of various members of the insulin-like growth factor and TOR signaling pathways resulted in anomalous PSC cell production, leading to a defective niche organization. Further analysis of the Pten, TSC1, and TSC2 tumor suppressor genes demonstrated their loss-of-function condition resulted in severely altered blood cell homeostasis, including the abundant production of lamellocytes, specialized hemocytes involved in innate immune responses. Together, this cell-specific RNAi knockdown survey and mutant phenotype analyses identified multiple genes and their regulatory networks required for the normal organization and function of the hematopoietic progenitor niche within the lymph gland.
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46
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Fossett N. Signal transduction pathways, intrinsic regulators, and the control of cell fate choice. Biochim Biophys Acta Gen Subj 2012; 1830:2375-84. [PMID: 22705942 DOI: 10.1016/j.bbagen.2012.06.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 05/10/2012] [Accepted: 06/07/2012] [Indexed: 12/14/2022]
Abstract
BACKGROUND Information regarding changes in organismal status is transmitted to the stem cell regulatory machinery by a limited number of signal transduction pathways. Consequently, these pathways derive their functional specificity through interactions with stem cell intrinsic master regulators, notably transcription factors. Identifying the molecular underpinnings of these interactions is critical to understanding stem cell function. SCOPE OF REVIEW This review focuses on studies in Drosophila that identify the gene regulatory basis for interactions between three different signal transduction pathways and an intrinsic master transcriptional regulator in the context of hematopoietic stem-like cell fate choice. Specifically, the interface between the GATA:FOG regulatory complex and the JAK/STAT, BMP, and Hedgehog pathways is examined. MAJOR CONCLUSIONS The GATA:FOG complex coordinates information transmitted by at least three different signal transduction pathways as a means to control stem-like cell fate choice. This illustrates emerging principles concerning regulation of stem cell function and describes a gene regulatory link between changes in organismal status and stem cell response. GENERAL SIGNIFICANCE The Drosophila model system offers a powerful approach to identify the molecular basis of how stem cells receive, interpret, and then respond to changes in organismal status. This article is part of a Special Issue entitled: Biochemistry of Stem Cells.
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Affiliation(s)
- Nancy Fossett
- Center for Vascular and Inflammatory Diseases and the Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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47
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Benmimoun B, Polesello C, Waltzer L, Haenlin M. Dual role for Insulin/TOR signaling in the control of hematopoietic progenitor maintenance in Drosophila. Development 2012; 139:1713-7. [PMID: 22510984 DOI: 10.1242/dev.080259] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The interconnected Insulin/IGF signaling (IlS) and Target of Rapamycin (TOR) signaling pathways constitute the main branches of the nutrient-sensing system that couples growth to nutritional conditions in Drosophila. Here, we addressed the influence of these pathways and of diet restriction on the balance between the maintenance of multipotent hematopoietic progenitors and their differentiation in the Drosophila lymph gland. In this larval hematopoietic organ, a pool of stem-like progenitor blood cells (prohemocytes) is kept undifferentiated in response to signaling from a specialized group of cells forming the posterior signaling center (PSC), which serves as a stem cell niche. We show that, reminiscent of the situation in human, loss of the negative regulator of IIS Pten results in lymph gland hyperplasia, aberrant blood cell differentiation and hematopoietic progenitor exhaustion. Using site-directed loss- and gain-of-function analysis, we demonstrate that components of the IIS/TOR pathways control lymph gland homeostasis at two levels. First, they cell-autonomously regulate the size and activity of the hematopoietic niche. Second, they are required within the prohemocytes to control their growth and maintenance. Moreover, we show that diet restriction or genetic alteration mimicking amino acid deprivation triggers progenitor cell differentiation. Hence, our study highlights the role of the IIS/TOR pathways in orchestrating hematopoietic progenitor fate and links blood cell fate to nutritional status.
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Affiliation(s)
- Billel Benmimoun
- Université de Toulouse, UPS, CBD (Centre de Biologie du Développement), Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France
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48
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Neurofibromatosis-like phenotype in Drosophila caused by lack of glucosylceramide extension. Proc Natl Acad Sci U S A 2012; 109:6987-92. [PMID: 22493273 DOI: 10.1073/pnas.1115453109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Glycosphingolipids (GSLs) are of fundamental importance in the nervous system. However, the molecular details associated with GSL function are largely unknown, in part because of the complexity of GSL biosynthesis in vertebrates. In Drosophila, only one major GSL biosynthetic pathway exists, controlled by the glycosyltransferase Egghead (Egh). Here we discovered that loss of Egh causes overgrowth of peripheral nerves and attraction of immune cells to the nerves. This phenotype is reminiscent of the human disorder neurofibromatosis type 1, which is characterized by disfiguring nerve sheath tumors with mast cell infiltration, increased cancer risk, and learning deficits. Neurofibromatosis type 1 is due to a reduction of the tumor suppressor neurofibromin, a negative regulator of the small GTPase Ras. Enhanced Ras signaling promotes glial growth through activation of phosphatidylinositol 3-kinase (PI3K) and its downstream kinase Akt. We find that overgrowth of peripheral nerves in egh mutants is suppressed by down-regulation of the PI3K signaling pathway by expression of either dominant-negative PI3K, the tumor suppressor PTEN, or the transcription factor FOXO in the subperineurial glia. These results show that loss of the glycosyltransferase Egh affects membrane signaling and activation of PI3K signaling in glia of the peripheral nervous system, and suggest that glycosyltransferases may suppress proliferation.
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49
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Kroeger PT, Tokusumi T, Schulz RA. Transcriptional regulation of eater gene expression in Drosophila blood cells. Genesis 2012; 50:41-9. [PMID: 21809435 DOI: 10.1002/dvg.20787] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/13/2011] [Accepted: 07/14/2011] [Indexed: 12/25/2022]
Abstract
Eater is a transmembrane protein that mediates phagocytosis in Drosophila. eater was identified in a microarray analysis of genes downregulated in S2 cells, in which Serpent had been knocked down by RNAi. The gene was shown to be expressed predominantly in plasmatocytes after embryonic development. We have extensively analyzed the transcriptional enhancer controlling eater expression with the following findings: the enhancer reproduces the plasmatocyte expression pattern of the gene as verified by anti-P1 antibody staining and a 526-basepair DNA region is active in lymph gland and hemolymph plasmatocytes. This DNA contains several GATA elements that serve as putative-binding sites for Serpent. Site-directed mutagenesis of two of these GATA sites abolishes eater expression in both lymph gland and hemolymph plasmatocytes. This suggests that Serpent regulates eater expression by binding these GATA sites, which was confirmed by gel shift analysis. These analyses allowed us to use eater-Gal4 to force plasmatocyte to lamellocyte differentiation.
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Affiliation(s)
- Paul T Kroeger
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Limpert E, Stahel WA. Problems with using the normal distribution--and ways to improve quality and efficiency of data analysis. PLoS One 2011; 6:e21403. [PMID: 21779325 PMCID: PMC3136454 DOI: 10.1371/journal.pone.0021403] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 06/01/2011] [Indexed: 02/02/2023] Open
Abstract
Background The Gaussian or normal distribution is the most established model to characterize quantitative variation of original data. Accordingly, data are summarized using the arithmetic mean and the standard deviation, by ± SD, or with the standard error of the mean, ± SEM. This, together with corresponding bars in graphical displays has become the standard to characterize variation. Methodology/Principal Findings Here we question the adequacy of this characterization, and of the model. The published literature provides numerous examples for which such descriptions appear inappropriate because, based on the “95% range check”, their distributions are obviously skewed. In these cases, the symmetric characterization is a poor description and may trigger wrong conclusions. To solve the problem, it is enlightening to regard causes of variation. Multiplicative causes are by far more important than additive ones, in general, and benefit from a multiplicative (or log-) normal approach. Fortunately, quite similar to the normal, the log-normal distribution can now be handled easily and characterized at the level of the original data with the help of both, a new sign, x/, times-divide, and notation. Analogous to ± SD, it connects the multiplicative (or geometric) mean * and the multiplicative standard deviation s* in the form * x/s*, that is advantageous and recommended. Conclusions/Significance The corresponding shift from the symmetric to the asymmetric view will substantially increase both, recognition of data distributions, and interpretation quality. It will allow for savings in sample size that can be considerable. Moreover, this is in line with ethical responsibility. Adequate models will improve concepts and theories, and provide deeper insight into science and life.
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Affiliation(s)
| | - Werner A. Stahel
- Seminar for Statistics, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
- * E-mail:
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