Myelopoiesis in the zebrafish, Danio rerio

Bennett, Carolyn M.; Kanki, John P.; Rhodes, Jennifer; Liu, Ting X.; Paw, Barry H.; Kieran, Mark W.; Langenau, David M.; Delahaye-Brown, Anne; Zon, Leonard I.; Fleming, Mark D.; Look, A. Thomas

doi:10.1182/blood.v98.3.643

Cited by 390 publications

(420 citation statements)

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“…Larvae were labelled with anti‐L‐plastin, which stains phagocytic cells according to established protocols (Bennett et al, 2001; Herbomel, Thisse, & Thisse, 1999). In short, larvae were rinsed with 1% PBTx, (1% Triton X‐100 in PBS), permeated in 0.24% trypsin in PBS and blocked for 3 hr in block buffer (10% normal goat serum [NGS] in 1% PBTx).…”

Section: Methodsmentioning

confidence: 99%

Mycobacteria employ two different mechanisms to cross the blood-brain barrier

Leeuwen

Boot

Kuijl

et al. 2018

Cellular Microbiology

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Central nervous system (CNS) infection by Mycobacterium tuberculosis is one of the most devastating complications of tuberculosis, in particular in early childhood. In order to induce CNS infection, M. tuberculosis needs to cross specialised barriers protecting the brain. How M. tuberculosis crosses the blood–brain barrier (BBB) and enters the CNS is not well understood. Here, we use transparent zebrafish larvae and the closely related pathogen Mycobacterium marinum to answer this question. We show that in the early stages of development, mycobacteria rapidly infect brain tissue, either as free mycobacteria or within circulating macrophages. After the formation of a functionally intact BBB, the infiltration of brain tissue by infected macrophages is delayed, but not blocked, suggesting that crossing the BBB via phagocytic cells is one of the mechanisms used by mycobacteria to invade the CNS. Interestingly, depletion of phagocytic cells did not prevent M. marinum from infecting the brain tissue, indicating that free mycobacteria can independently cause brain infection. Detailed analysis showed that mycobacteria are able to cause vasculitis by extracellular outgrowth in the smaller blood vessels and by infecting endothelial cells. Importantly, we could show that this second mechanism is an active process that depends on an intact ESX‐1 secretion system, which extends the role of ESX‐1 secretion beyond the macrophage infection cycle.

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Section: Methodsmentioning

confidence: 99%

Mycobacteria employ two different mechanisms to cross the blood-brain barrier

Leeuwen

Boot

Kuijl

et al. 2018

Cellular Microbiology

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“…As in mammals, the cells of the zebrafish immune system include lymphocytes, neutrophils, and macrophages (49), as well as dendritic cells (50), eosinophils (51,52), human mast cell-like cells (53), and natural killer cells (54). Our flow cytometric analyses of furinA td204e/ϩ mutant fish kidneys (the primary site of hematopoiesis in fish) showed normal numbers of lymphocytes, blood cell precursors, and erythrocytes, but low granulocyte counts, indicating that FurinA promotes granulopoiesis.…”

Section: Discussionmentioning

confidence: 99%

The Proprotein Convertase Subtilisin/Kexin FurinA Regulates Zebrafish Host Response against Mycobacterium marinum

et al. 2015

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Tuberculosis is a chronic bacterial disease with a complex pathogenesis. An effective immunity against Mycobacterium tuberculosis requires both the innate and adaptive immune responses, including proper T helper (Th) type 1 cell function. FURIN is a proprotein convertase subtilisin/kexin (PCSK) enzyme, which is highly expressed in Th1 type cells. FURIN expression in T cells is essential for maintaining peripheral immune tolerance, but its role in the innate immunity and infections has remained elusive. Here, we utilized Mycobacterium marinum infection models in zebrafish (Danio rerio) to investigate how furin regulates host responses against mycobacteria. In steady-state furinA td204e/؉ fish reduced furinA mRNA levels associated with low granulocyte counts and elevated Th cell transcription factor expressions. Silencing furin genes reduced the survival of M. marinuminfected zebrafish embryos. A mycobacterial infection upregulated furinA in adult zebrafish, and infected furinA td204e/؉ mutants exhibited a proinflammatory phenotype characterized by elevated tumor necrosis factor a (tnfa), lymphotoxin alpha (lta) and interleukin 17a/f3 (il17a/f3) expression levels. The enhanced innate immune response in the furinA td204e/؉ mutants correlated with a significantly decreased bacterial burden in a chronic M. marinum infection model. Our data show that upregulated furinA expression can serve as a marker for mycobacterial disease, since it inhibits early host responses and consequently promotes bacterial growth in a chronic infection.T uberculosis (TB) is an epidemic infectious disease caused by the mycobacterial species Mycobacterium tuberculosis (1, 2). Circa 13% of the individuals with active TB were simultaneous carriers of the human immunodeficiency virus (HIV), and almost one-third of TB-associated deaths occurred among HIV ϩ patients, demonstrating the critical role of cluster of differentiation 4 (CD4 ϩ ) T lymphocyte-mediated immunity in the control of M. tuberculosis infection (3, 4). More specifically, the adaptive immunity against TB is primarily mediated by T helper (Th) type 1 cells, as is suggested by the gene expression profile upon infection (5), as well as the infection-induced mortality of gamma interferon-deficient (6, 7) and interleukin-12 (IL-12)-deficient (8) mice.The proprotein convertase subtilisin/kexin (PCSK) enzymes are a family of serine endoproteases with nine members in humans: PCSK1 and -2, FURIN, PCSK4 to -7, membrane-bound transcription factor peptidase site 1 (MBTPS1), and PCSK9 (9). Typically, PCSKs convert precursor proteins (proproteins) into their biologically active forms by cleaving them at specific target motifs made up of the basic amino acids lysine and arginine (9, 10). FURIN was the first identified mammalian PCSK and is present in vertebrates and many invertebrates (11,12). A series of in vitro experiments have suggested a central role for FURIN in host defense because it proteolytically activates several immunoregulatory proproteins, such as membrane-inserted matrix metallo...

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“…Moreover, markers for myeloid (MPO and Lplastin) and thrombocyte (platelet-equivalent, cd41) lineages were normal in the hrg-1 morphant embryos ( Supplementary Fig. 3b, c) 17,18 . These findings indicate that zebrafish hrg-1 is not required for cell lineage specification but rather for maintenance and haemoglobinization of the embryonic erythroid cells.…”

mentioning

confidence: 99%

Haem homeostasis is regulated by the conserved and concerted functions of HRG-1 proteins

Rajagopal

Rao

Amigo

et al. 2008

Nature

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271

383

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Haems are metalloporphyrins that serve as prosthetic groups for various biological processes including respiration, gas sensing, xenobiotic detoxification, cell differentiation, circadian clock control, metabolic reprogramming and microRNA processing [1][2][3][4] . With a few exceptions, haem is synthesized by a multistep biosynthetic pathway comprising defined intermediates that are highly conserved throughout evolution 5 . Despite our extensive knowledge of haem biosynthesis and degradation, the cellular pathways and molecules that mediate intracellular haem trafficking are unknown. The experimental setback in identifying haem trafficking pathways has been the inability to dissociate the highly regulated cellular synthesis and degradation of haem from intracellular trafficking events 6 . Caenorhabditis elegans and related helminths are natural haem auxotrophs that acquire environmental haem for incorporation into haemoproteins, which have vertebrate orthologues 7 . Here we show, by exploiting this auxotrophy to identify HRG-1 proteins in C. elegans, that these proteins are essential for haem homeostasis and normal development in worms and vertebrates. Depletion of hrg-1, or its paralogue hrg-4, in worms results in the disruption of organismal haem sensing and an abnormal response to haem analogues. HRG-1 andCorrespondence and requests for materials should be addressed to I.H. (hamza@umd.edu). Supplementary Information is linked to the online version of the paper at www.nature.com/nature.Author Contributions Experimental design and execution were as follows: worm experiments and microarrays, A.R., A.U.R., M.K. and I.H.; mammalian experiments, A.R., A.U.R., M.T., C.H., S.U., M. HRG-4 are previously unknown transmembrane proteins, which reside in distinct intracellular compartments. Transient knockdown of hrg-1 in zebrafish leads to hydrocephalus, yolk tube malformations and, most strikingly, profound defects in erythropoiesis-phenotypes that are fully rescued by worm HRG-1. Human and worm proteins localize together, and bind and transport haem, thus establishing an evolutionarily conserved function for HRG-1. These findings reveal conserved pathways for cellular haem trafficking in animals that define the model for eukaryotic haem transport. Thus, uncovering the mechanisms of haem transport in C. elegans may provide insights into human disorders of haem metabolism and reveal new drug targets for developing anthelminthics to combat worm infestations.In animals, the terminal enzyme in haem synthesis, ferrochelatase, is located on the matrix side of the inner mitochondrial membrane 8 . Most newly synthesized haem must be transported through mitochondrial membranes to haemoproteins found in distinct intracellular membrane compartments 6 . Haem synthesis is regulated at multiple steps by effectors including iron, haem and oxygen to prevent the uncoordinated accumulation of haem or its precursors 5 . C. elegans is a haem auxotroph and is therefore a unique genetic animal model in which to identify the molecule...

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Myelopoiesis in the zebrafish, Danio rerio

Cited by 390 publications

References 39 publications

Mycobacteria employ two different mechanisms to cross the blood-brain barrier

Mycobacteria employ two different mechanisms to cross the blood-brain barrier

The Proprotein Convertase Subtilisin/Kexin FurinA Regulates Zebrafish Host Response against Mycobacterium marinum

Haem homeostasis is regulated by the conserved and concerted functions of HRG-1 proteins

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