Studying the adaptive immune system in zebrafish by transplantation of hematopoietic precursor cells

Biliatresone: progress in biliary atresia study

BACKGROUND

Biliary atresia (BA) is one of the main causes of neonatal end-stage liver disease. Without timely diagnosis and treatment, most children with BA will develop irreversible liver fibrosis within the first two months. While current theorized causes of BA include viral infection, immune disorders, and genetic defects, the comprehensive etiology is still largely unknown. Recently, biliatresone attracted much interest for its ability to induce BA in both zebrafish and mice, so we summarized the latest progress of biliatresone research in BA and tried to answer the question of whether it could provide further clues to the etiology of human BA.

DATA SOURCES

We conducted a PubMed search for any published articles related to the topic using search terms including "biliary atresia", "biliatresone", "GSH", and "HSP90". Relevant data were extracted from the original text or supplementary materials of the corresponding articles.

RESULTS

Biliatresone had shown its unique toxicity in multiple species such as zebrafish and mice, and pathogenic factors involved included glutathione (GSH), heat shock protein 90 (HSP90) and the related pathways. In combination with epidemiological evidence and recent studies on the intestinal flora in biliary atresia, a new pathogenic hypothesis that the occurrence of biliary atresia is partly due to biliatresone or its structure-like compounds depositing in human body via vegetables or/and the altered intestinal flora structure can be tentatively established.

CONCLUSIONS

Based on the existing evidence, we emphasized that GSH and HSP90 are involved in the development of BA, and the maternal diet, especially higher vegetable intake of Asian women of childbearing age, accompanied by the altered intestinal flora structure, may contribute to the occurrence of biliary atresia and the higher incidence in the Asia group. However, the evidence from large sample epidemiological research is necessary.

Stage-specific and cell type-specific requirements of ikzf1 during haematopoietic differentiation in zebrafish

The zinc finger transcription factor Ikaros1 (Ikzf1) is required for lymphoid development in mammals. Four zinc fingers constitute its DNA binding domain and two zinc fingers are present in the C-terminal protein interaction module. We describe the phenotypes of zebrafish homozygous for two distinct mutant ikzf1 alleles. The IT325 variant lacks the C-terminal two zinc fingers, whereas the fr105 variant retains only the first zinc finger of the DNA binding domain. An intact ikzf1 gene is required for larval T cell development, whereas low levels of adult lymphoid development recover in the mutants. By contrast, the mutants exhibit a signature of increased myelopoiesis at larval and adult stages. Both mutations stimulate erythroid differentiation in larvae, indicating that the C-terminal zinc fingers negatively regulate the extent of red blood cell production. An unexpected differential effect of the two mutants on adult erythropoiesis suggests a direct requirement of an intact DNA binding domain for entry of progenitors into the red blood cell lineage. Collectively, our results reinforce the biological differences between larval and adult haematopoiesis, indicate a stage-specific function of ikzf1 in regulating the hierarchical bifurcations of differentiation, and assign distinct functions to the DNA binding domain and the C-terminal zinc fingers.

One Host-Multiple Applications: Zebrafish (Danio rerio) as Promising Model for Studying Human Cancers and Pathogenic Diseases

In recent years, zebrafish (ZF) has been increasingly applied as a model in human disease studies, with a particular focus on cancer. A number of advantages make it an attractive alternative for mice widely used so far. Due to the many advantages of zebrafish, modifications can be based on different mechanisms and the induction of human disease can take different forms depending on the research goal. Genetic manipulation, tumor transplantation, or injection of the pathogen are only a few examples of using ZF as a model. Most of the studies are conducted in order to understand the disease mechanism, monitor disease progression, test new or alternative therapies, and select the best treatment. The transplantation of cancer cells derived from patients enables the development of personalized medicine. To better mimic a patient’s body environment, immune-deficient models (SCID) have been developed. A lower immune response is mostly generated by genetic manipulation but also by irradiation or dexamethasone treatment. For many studies, using SCID provides a better chance to avoid cancer cell rejection. In this review, we describe the main directions of using ZF in research, explain why and how zebrafish can be used as a model, what kind of limitations will be met and how to overcome them. We collected recent achievements in this field, indicating promising perspectives for the future.

Variations of enzymatic activity and gene expression in zebrafish (Danio rerio) embryos co-exposed to zearalenone and fumonisin B1

The natural co-occurrence of multiple mycotoxins has been reported in cereals and cereal products worldwide. Even though the dietary exposure to mycotoxins constitutes a serious human health, most reports are limited to the toxic effect of individual mycotoxins. The purpose of the present study was to assess the combined toxic effects of zearalenone (ZEN) and fumonisin B1 (FB1) and the potential interaction of their mixture on zebrafish (Danio rerio) embryos. Our results showed that ZEN possessed the higher toxicity to embryonic zebrafish (7-day LC₅₀ value of 0.78 mg a.i. L^-1) compared with FB1 (7-day LC₅₀ value of 227.7 mg a.i. L^-1). The combination of ZEN and FB1 exerted an additive effect on zebrafish embryos. Meanwhile, the activities of antioxidant CAT, caspase-3, and detoxification enzyme CYP450, as well as the expressions of six genes (Mn-sod, cas9, bax, cc-chem, ERα, and crh) associated with oxidative stress, cellular apoptosis, immune system, and endocrine system were prominently altered in the mixture exposure compared with the corresponding single treatment group of ZEN or FB1. Taken together, the regulatory standards of mycotoxins in food and feed should be updated based on the mixture effects of mycotoxins, and there is an increased need on effective detoxification methods for controlling and reducing the toxicity of multiple mycotoxins in animal feed and throughout the food supply chain.

Tipping the Scales With Zebrafish to Understand Adaptive Tumor Immunity

The future of improved immunotherapy against cancer depends on an in-depth understanding of the dynamic interactions between the immune system and tumors. Over the past two decades, the zebrafish has served as a valuable model system to provide fresh insights into both the development of the immune system and the etiologies of many different cancers. This well-established foundation of knowledge combined with the imaging and genetic capacities of the zebrafish provides a new frontier in cancer immunology research. In this review, we provide an overview of the development of the zebrafish immune system along with a side-by-side comparison of its human counterpart. We then introduce components of the adaptive immune system with a focus on their roles in the tumor microenvironment (TME) of teleosts. In addition, we summarize zebrafish models developed for the study of cancer and adaptive immunity along with other available tools and technology afforded by this experimental system. Finally, we discuss some recent research conducted using the zebrafish to investigate adaptive immune cell-tumor interactions. Without a doubt, the zebrafish will arise as one of the driving forces to help expand the knowledge of tumor immunity and facilitate the development of improved anti-cancer immunotherapy in the foreseeable future.

Leveraging the zebrafish to model organ transplantation

PURPOSE OF REVIEW

The availability of organs for transplant fails to meet the demand and this shortage is growing worse every year. As the cost of not getting a suitable donor organ can mean death for patients, new tools and approaches that allows us to make advances in transplantation faster and provide a different vantage point are required. To address this need, we introduce the concept of using the zebrafish (Danio rerio) as a new model system in organ transplantation. The zebrafish community offers decades of research experience in disease modeling and a rich toolbox of approaches for interrogating complex pathological states. We provide examples of how already existing zebrafish assays/tools from cancer, regenerative medicine, immunology, and others, could be leveraged to fuel new discoveries in pursuit of solving the organ shortage.

RECENT FINDINGS

Important innovations have enabled several types of transplants to be successfully performed in zebrafish, including stem cells, tumors, parenchymal cells, and even a partial heart transplant. These innovations have been performed against a backdrop of an expansive and impressive list of tools designed to uncover the biology of complex systems that include a wide array of fluorescent transgenic fish that label specific cell types and mutant lines that are transparent, immune-deficient. Allogeneic transplants can also be accomplished using immune suppressed and syngeneic fish. Each of these innovations within the zebrafish community would provide several helpful tools that could be applied to transplant research.

SUMMARY

We highlight some examples of existing tools and assays developed in the zebrafish community that could be leveraged to overcome barriers in organ transplantation, including ischemia-reperfusion, short preservation durations, regeneration of marginal grafts, and acute and chronic rejection.

Zebrafish, a model to develop nanotherapeutics that control neutrophils response during inflammation

Neutrophils are crucial modulators of the inflammation process, and their uncontrolled response worsens several chronic pathologies. The p38 mitogen-activated protein kinases (MAPKs) activity is critical for normal immune and inflammatory response through the regulation of pro-inflammatory cytokines synthesis. In this work, we study the effect of hybrid lipid-polymer nanoparticles loaded with the p38 MAPK inhibitor SB203580 in an acute and chronic inflammatory model in zebrafish containing a transgenic neutrophil cell line that constitutively expresses a green fluorescent protein. We identify the existence of at least two neutrophils subpopulation involved in the response during the acute inflammation triggered; a first-responder p38α-independent subset and a second-responder p38α-dependent subset. In the case of chronic inflammation, neutrophils recruited in the intestine only during the inflammation process, migrate in a p38α-dependent manner. Likewise, we establish that SB203580-loaded in NPs exerts their action during at least a double period than the inhibitor administers directly in both types of inflammation. Our results demonstrate the exceptional potential of the zebrafish as an inflammatory model for studying novel nanotherapeutics that selectively inhibit the neutrophils response, and to identify functional neutrophils subpopulations involved in the inflammation process.

Zebrafish Xenografts for the In Vivo Analysis of Healthy and Malignant Human Hematopoietic Cells

The zebrafish is a powerful vertebrate model for genetic studies on embryonic development and organogenesis. In the last decades, zebrafish were furthermore increasingly used for disease modeling and investigation of cancer biology. Zebrafish are particularly used for mutagenesis and small molecule screens, as well as for live imaging assays that provide unique opportunities to monitor cell behavior, both on a single cell and whole organism level in real time. Zebrafish have been also used for in vivo investigations of human cells transplanted into embryos or adult animals; this zebrafish xenograft model can be considered as an intermediate assay between in vitro techniques and more time-consuming and expensive mammalian models.Here, we present a protocol for transplantation of healthy and malignant human hematopoietic cells into larval zebrafish; transplantation into adult zebrafish and possible advantages and limitations of the zebrafish compared to murine xenograft models are discussed.

Next-Generation Immune Repertoire Sequencing as a Clue to Elucidate the Landscape of Immune Modulation by Host-Gut Microbiome Interactions

The human immune system is a fine network consisted of the innumerable numbers of functional cells that balance the immunity and tolerance against various endogenous and environmental challenges. Although advances in modern immunology have revealed a role of many unique immune cell subsets, technologies that enable us to capture the whole landscape of immune responses against specific antigens have been not available to date. Acquired immunity against various microorganisms including host microbiome is principally founded on T cell and B cell populations, each of which expresses antigen-specific receptors that define a unique clonotype. Over the past several years, high-throughput next-generation sequencing has been developed as a powerful tool to profile T- and B-cell receptor repertoires in a given individual at the single-cell level. Sophisticated immuno-bioinformatic analyses by use of this innovative methodology have been already implemented in clinical development of antibody engineering, vaccine design, and cellular immunotherapy. In this article, we aim to discuss the possible application of high-throughput immune receptor sequencing in the field of nutritional and intestinal immunology. Although there are still unsolved caveats, this emerging technology combined with single-cell transcriptomics/proteomics provides a critical tool to unveil the previously unrecognized principle of host–microbiome immune homeostasis. Accumulation of such knowledge will lead to the development of effective ways for personalized immune modulation through deeper understanding of the mechanisms by which the intestinal environment affects our immune ecosystem.

Interleukin 4/13 receptors: An overview of genes, expression and functional role in teleost fish

In superior vertebrates, Interleukin 4 (IL-4) and Interleukin 13 (IL-13) play key and diverse roles to support immune responses acting on cell surface receptors. When stimulated, receptors activate intracellular signalling cascades switching cell phenotypes according to stimuli. In teleost fish, Interleukin 4/13 (IL-4/13) is the ancestral family cytokine related to both IL-4 and IL-13. Every private and common receptor subunit for IL-4/13 have in fish at least two paralogues and, as in mammals, soluble forms are also part of the receptor system. Reports for findings of fish IL-4/13 receptors have covered comparative analysis, transcriptomic profiles and to a lesser extent, functional analysis regarding ligand-receptor interactions and their biological effects. This review addresses available information from fish IL-4/13 receptors and discusses overall implications on teleost immunity, summarized gene induction strategies and pathogen-induced gene modulation, which may be useful tools to enhance immune response. Additionally, we present novel coding sequences for Atlantic salmon (Salmo salar) common gamma chain receptor (γC), Interleukin 13 receptor alpha 1A chain (IL-13Rα1A) and Interleukin 13 receptor alpha 1B chain (IL-13Rα1B).