Janus Kinase 3 (JAK3): A Critical Conserved Node in Immunity Disrupted in Immune Cell Cancer and Immunodeficiency

The Janus kinase (JAK) family is a small group of protein tyrosine kinases that represent a central component of intracellular signaling downstream from a myriad of cytokine receptors. The JAK3 family member performs a particularly important role in facilitating signal transduction for a key set of cytokine receptors that are essential for immune cell development and function. Mutations that impact JAK3 activity have been identified in a number of human diseases, including somatic gain-of-function (GOF) mutations associated with immune cell malignancies and germline loss-of-function (LOF) mutations associated with immunodeficiency. The structure, function and impacts of both GOF and LOF mutations of JAK3 are highly conserved, making animal models highly informative. This review details the biology of JAK3 and the impact of its perturbation in immune cell-related diseases, including relevant animal studies.

The Role of Cytokine-Inducible SH2 Domain-Containing Protein (CISH) in the Regulation of Basal and Cytokine-Mediated Myelopoiesis

Cytokine-inducible SH2 domain-containing protein (CISH) is a member of the suppressor of cytokine signaling (SOCS) family of negative feedback regulators shown to play crucial roles in lymphoid cell development and function as well as appetite regulation. It has also been implicated in the control of signaling downstream of the receptors for the cytokines granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) in myeloid cells. To investigate the physiological role of CISH in myelopoiesis, mice deficient in CISH were analyzed basally and in response to administration of these cytokines. CISH knockout (KO) mice possessed basally elevated neutrophils in the blood, bone marrow, and spleen compared to wild-type (WT) mice. During GM-CSF-induced myelopoiesis, the frequency of neutrophils, myeloid dendritic cells (DCs), and CFU-M in the bone marrow was higher in the KO, as were the neutrophils and CFU-G in the spleen. In contrast, no differences were observed between KO and WT mice during G-CSF-induced myelopoiesis apart from an elevated frequency of CFU-G and CFU-M in the spleen. This work has identified a role for CISH in the negative regulation of granulopoiesis, including that mediated by GM-CSF.

N-Terminomic Changes in Neurons During Excitotoxicity Reveal Proteolytic Events Associated With Synaptic Dysfunctions and Potential Targets for Neuroprotection

Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death. We found that most proteolytically processed proteins in excitotoxic neurons are likely substrates of calpains, including key synaptic regulatory proteins such as CRMP2, doublecortin-like kinase I, Src tyrosine kinase and calmodulin-dependent protein kinase IIβ (CaMKIIβ). Critically, calpain-catalyzed proteolytic processing of these proteins generates stable truncated fragments with altered activities that potentially contribute to neuronal death by perturbing synaptic organization and function. Blocking calpain-mediated proteolysis of one of these proteins, Src, protected against neuronal loss in a rat model of neurotoxicity. Extrapolation of our N-terminomic results led to the discovery that CaMKIIα, an isoform of CaMKIIβ, undergoes differential processing in mouse brains under physiological conditions and during ischemic stroke. In summary, by identifying the neuronal proteins undergoing proteolysis during excitotoxicity, our findings offer new insights into excitotoxic neuronal death mechanisms and reveal potential neuroprotective targets for neurological disorders.

Zebrafish: A Relevant Genetic Model for Human Primary Immunodeficiency (PID) Disorders?

Primary immunodeficiency (PID) disorders, also commonly referred to as inborn errors of immunity, are a heterogenous group of human genetic diseases characterized by defects in immune cell development and/or function. Since these disorders are generally uncommon and occur on a variable background profile of potential genetic and environmental modifiers, animal models are critical to provide mechanistic insights as well as to create platforms to underpin therapeutic development. This review aims to review the relevance of zebrafish as an alternative genetic model for PIDs. It provides an overview of the conservation of the zebrafish immune system and details specific examples of zebrafish models for a multitude of specific human PIDs across a range of distinct categories, including severe combined immunodeficiency (SCID), combined immunodeficiency (CID), multi-system immunodeficiency, autoinflammatory disorders, neutropenia and defects in leucocyte mobility and respiratory burst. It also describes some of the diverse applications of these models, particularly in the fields of microbiology, immunology, regenerative biology and oncology.

Leukemia-associated truncation of granulocyte colony-stimulating factor receptor impacts granulopoiesis throughout the life-course

Introduction

The granulocyte colony-stimulating factor receptor (G-CSFR), encoded by the CSF3R gene, is involved in the production and function of neutrophilic granulocytes. Somatic mutations in CSF3R leading to truncated G-CSFR forms are observed in acute myeloid leukemia (AML), particularly those subsequent to severe chronic neutropenia (SCN), as well as in a subset of patients with other leukemias.

Methods

This investigation introduced equivalent mutations into the zebrafish csf3r gene via genome editing and used a range of molecular and cellular techniques to understand the impact of these mutations on immune cells across the lifespan.

Results

Zebrafish harboring truncated G-CSFRs showed significantly enhanced neutrophil production throughout successive waves of embryonic hematopoiesis and a neutrophil maturation defect in adults, with the mutations acting in a partially dominant manner.

Discussion

This study has elucidated new insights into the impact of G-CSFR truncations throughout the life-course and created a bone fide zebrafish model for further investigation.

Phylogenetic and Expression Analysis of Fos Transcription Factors in Zebrafish

Members of the FOS protein family regulate gene expression responses to a multitude of extracellular signals and are dysregulated in several pathological states. Whilst mouse genetic models have provided key insights into the tissue-specific functions of these proteins in vivo, little is known about their roles during early vertebrate embryonic development. This study examined the potential of using zebrafish as a model for such studies and, more broadly, for investigating the mechanisms regulating the functions of Fos proteins in vivo. Through phylogenetic and sequence analysis, we identified six zebrafish FOS orthologues, fosaa, fosab, fosb, fosl1a, fosl1b, and fosl2, which show high conservation in key regulatory domains and post-translational modification sites compared to their equivalent human proteins. During embryogenesis, zebrafish fos genes exhibit both overlapping and distinct spatiotemporal patterns of expression in specific cell types and tissues. Most fos genes are also expressed in a variety of adult zebrafish tissues. As in humans, we also found that expression of zebrafish FOS orthologs is induced by oncogenic BRAF-ERK signalling in zebrafish melanomas. These findings suggest that zebrafish represent an alternate model to mice for investigating the regulation and functions of Fos proteins in vertebrate embryonic and adult tissues, and cancer.

Generation and Characterization of a Zebrafish IL-2Rγc SCID Model

The IL-2 family of cytokines act via receptor complexes that share the interleukin-2 receptor gamma common (IL-2Rγc) chain to play key roles in lymphopoiesis. Inactivating IL-2Rγc mutations results in severe combined immunodeficiency (SCID) in humans and other species. This study sought to generate an equivalent zebrafish SCID model. The zebrafish il2rga gene was targeted for genome editing using TALENs and presumed loss-of-function alleles analyzed with respect to immune cell development and impacts on intestinal microbiota and tumor immunity. Knockout of zebrafish Il-2rγc.a resulted in a SCID phenotype, including a significant reduction in T cells, with NK cells also impacted. This resulted in dysregulated intestinal microbiota and defective immunity to tumor xenotransplants. Collectively, this establishes a useful zebrafish SCID model.

Acclimation of cadmium-induced genotoxicity and oxidative stress in mung bean seedlings by priming effect of phytohormones and proline

In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 μM), salicylic acid (SA) (50 μM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.

Xmrks the Spot: Fish Models for Investigating Epidermal Growth Factor Receptor Signaling in Cancer Research

Studies conducted in several fish species, e.g., Xiphophorus hellerii (green swordtail) and Xiphophorus maculatus (southern platyfish) crosses, Oryzias latipes (medaka), and Danio rerio (zebrafish), have identified an oncogenic role for the receptor tyrosine kinase, Xmrk, a gene product closely related to the human epidermal growth factor receptor (EGFR), which is associated with a wide variety of pathological conditions, including cancer. Comparative analyses of Xmrk and EGFR signal transduction in melanoma have shown that both utilize STAT5 signaling to regulate apoptosis and cell proliferation, PI3K to modulate apoptosis, FAK to control migration, and the Ras/Raf/MEK/MAPK pathway to regulate cell survival, proliferation, and differentiation. Further, Xmrk and EGFR may also modulate similar chemokine, extracellular matrix, oxidative stress, and microRNA signaling pathways in melanoma. In hepatocellular carcinoma (HCC), Xmrk and EGFR signaling utilize STAT5 to regulate cell proliferation, and Xmrk may signal through PI3K and FasR to modulate apoptosis. At the same time, both activate the Ras/Raf/MEK/MAPK pathway to regulate cell proliferation and E-cadherin signaling. Xmrk models of melanoma have shown that inhibitors of PI3K and MEK have an anti-cancer effect, and in HCC, that the steroidal drug, adrenosterone, can prevent metastasis and recover E-cadherin expression, suggesting that fish Xmrk models can exploit similarities with EGFR signal transduction to identify and study new chemotherapeutic drugs.

Zebrafish Bacterial Infection Assay to Study Host-Pathogen Interactions

The study of host-pathogen interactions has improved our understanding of both pathogenesis and the response of the host to infection, including both innate and adaptive responses. Neutrophils and macrophages represent the first line of innate host defense against any infection. The zebrafish is an ideal model to study the response of these cells to a variety of pathogens. Zebrafish possess both neutrophils and macrophages exhibiting similar defense mechanisms to their human counterparts. The transparency of zebrafish embryos greatly facilitates in vivo tracking of infection dynamics in a non-invasive manner at high-resolution using labelled pathogens, while immune cells can also be labelled transgenically to enable even more in-depth analysis. Here we describe a procedure for performing a bacterial infection assay in zebrafish embryos using fluorescently-labelled E. coli bacteria and demonstrate the monitoring and quantification of the infection kinetics. Of note, this procedure helps in understanding the functional role of genes that are important in driving the innate immune response.

Release of hazardous nanoplastic contaminants due to microplastics fragmentation under shear stress forces

The presence of nanoplastics in water has become a major environmental concern in the last decade however the knowledge on the origin and formation of these emerging contaminants is lacking due to analytical challenges in detection and quantification techniques. The release of nanoplastics due to the fragmentation of microplastics extracted from a facial scrub and the resulting toxicity on aquatic species are reported here for the first time. The daily use of 4 g of facial scrub could release up to 10¹¹ microplastics of 400 nm in size per litre of wastewater from household drains. Turbulences created by mixing or pumping induced the fragmentation of microplastics into nanoplastics smaller than 10 nm via a crack propagation and failure mechanism, increasing the number of particles in water by one order of magnitude. Compared to microplastics at a fixed concentration number of 6.8 × 10⁸ part./mL, the generated nanoplastics initiated the death of 54% more cells in zebrafish by passive ingestion via skin diffusion which therefore pose a real threat for aquatic living organisms. These results stress the need to reduce the release of nano/microplastics in the aquatic environment to prevent the contamination of all trophic levels.

Conserved IL-2Rγc Signaling Mediates Lymphopoiesis in Zebrafish

The IL-2 receptor γ common (IL-2Rγc) chain is the shared subunit of the receptors for the IL-2 family of cytokines, which mediate signaling through JAK3 and various downstream pathways to regulate lymphopoiesis. Inactivating mutations in human IL-2Rγc result in SCID, a primary immunodeficiency characterized by greatly reduced numbers of lymphocytes. This study used bioinformatics, expression analysis, gene ablation, and specific pharmacologic inhibitors to investigate the function of two putative zebrafish IL-2Rγc paralogs, il-2rγc.a and il-2rγc.b, and downstream signaling components during early lymphopoiesis. Expression of il-2rγc.a commenced at 16 h post fertilization (hpf) and rose steadily from 4-6 d postfertilization (dpf) in the developing thymus, with il-2rγc.a expression also confirmed in adult T and B lymphocytes. Transcripts of il-2rγc.b were first observed from 8 hpf, but waned from 16 hpf before reaching maximal expression at 6 dpf, but this was not evident in the thymus. Knockdown of il-2rγc.a, but not il-2rγc.b, substantially reduced embryonic lymphopoiesis without affecting other aspects of hematopoiesis. Specific targeting of zebrafish Jak3 exerted a similar effect on lymphopoiesis, whereas ablation of zebrafish Stat5.1 and pharmacologic inhibition of PI3K and MEK also produced significant but smaller effects. Ablation of il-2rγc.a was further demonstrated to lead to an absence of mature T cells, but not B cells in juvenile fish. These results indicate that conserved IL-2Rγc signaling via JAK3 plays a key role during early zebrafish lymphopoiesis, which can be potentially targeted to generate a zebrafish model of human SCID.

Biodegradation of m-cresol by aerobic granules in a sequencing batch reactor

The present study was aimed at the development of aerobic granules in a sequencing batch reactor for the biodegradation of m-cresol. The reactor was started with 100 mg L(-1)of m-cresol. Aerobic granules first appeared within 1 month of the start-up of the reactor. The granules were large and strong and had a compact structure. The diameter of stable granules on day 200 was in the range of 1.5 - 5 mm. The integrity coefficient and density of the granules was found to be 98% and 1046 kg m(-3), respectively. The settling velocity of the granules was found to be in the range of 2-6 x 10(-2) m s(-1). The aerobic granules were able to degrade m-cresol up to 800 mg L(-1) at a removal efficiency of 87%. UV and GC/MS studies confirmed that the biodegradation ofm-cresol occurred via catechol via the ortho-cleavage pathway. The specific m-cresol degradation rate in aerobic granules followed the Haldane model for substrate inhibition. A high specific m-cresol degradation rate of up to 0.718 g m-cresol g(-1)VSS(-1)d(-1) was sustained up to an m-cresol concentration of 400 mgL(-1). The higher removal efficiency and good settling characteristics of aerobic granules make the sequencing batch reactor method suitable for enhancing the microorganism potential for biodegradation of inhibitory compounds.