Noncanonical function of threonyl-tRNA synthetase regulates vascular development in zebrafish

Dipropyl phthalate induces craniofacial chondrogenic defects in zebrafish embryos

Dipropyl phthalate (DPRP), a plasticizer commonly utilized in the plastics industry, has been identified in food and the environment and has the potential to present a hazard to human health and the environment. In this study, the first comprehensive evaluation of DPRP-induced craniofacial chondrogenic defects was conducted using a zebrafish model. Zebrafish embryos were exposed to 1, 2, and 4 mg/L DPRP from 6 to 96 h post-fertilization. At 80 hpf, it was observed that exposure to DPRP resulted in craniofacial developmental malformations, which were mainly characterized by the shortening of the mandibular pharyngeal arches and the inability of the accompanying artery to elongate forward. The resulting phenotype was similar to that of micrognathia syndrome. Transcriptome sequencing and molecular docking analyses revealed that DPRP down-regulated chondrocyte-related genes and induced activation of the FoxO signaling pathway, which in turn interfered with cell proliferation and apoptosis. In this process, DPRP induced elevated levels of oxidative stress in the craniofacial pharyngeal arch while promoting inflammatory responses. This ultimately led to craniofacial chondrogenic malformations in zebrafish. The present study demonstrates that DPRP induces developmental toxicity of zebrafish craniofacial cartilage, which may have adverse effects on other aquatic organisms and humans.

3-Chloro-1,2-Propanediol Exposure Induces Cardiotoxicity and Behavioural Abnormalities in Zebrafish Embryos

Numerous contemporary diseases are linked to food contamination. Pathogenic agents might stem from certain food ingredients or result from pollution stemming from food processing or packaging. One such contaminant is 3-Chloro-1,2-propanediol (3-MCPD), it has been previously reported to be produced during the preparation of chemical sauces, as well as during the heating of baked goods. Yet, uncertainty surrounds its potential to induce embryonic developmental toxicity. In this study, zebrafish were employed as the focal point to assess the impact of 3-MCPD on initial embryonic development, heart functionality, and behavior. The research unveiled that exposure of zebrafish embryos to 18, 36, and 54 mM 3-MCPD led to cardiac anomalies, including pericardial edema, reduced heart rate, and elongated SV-BA distance. Additionally, 3-MCPD exposure triggered aberrations in cardiac-related gene expression and an elevation in oxidative stress. Notably, behavioral changes were observed in 3-MCPD-exposed zebrafish embryos, while vascular development appeared unaffected. This study introduces a novel basis for comprehensive exploration of 3-MCPD toxicity.

Isavuconazonium sulfate induces heart development defects in zebrafish larvae by upregulation of oxidative stress

Environmental pollution remains a pressing global concern, with a substantial number of annual fatalities attributed to pollution-induced diseases. One emerging facet of environmental pollution is drug contamination, whereby pharmaceutical compounds can readily infiltrate water sources during manufacturing or utilization, subsequently being detected in various aquatic ecosystems. Some drugs have been detected in many watersheds at concentrations that can cause toxicity to aquatic organisms. Isavuconazonium sulfate (ISAV-SF), a prevalent antifungal medication, is no exception, warranting an exploration of its potential toxicity. However, limited research has been conducted in this domain. In this investigation, zebrafish were employed as a model organism to scrutinize the cardiotoxicity of ISAV-SF. Exposure of zebrafish embryos to concentrations of 0.5, 0.75, and 1 mg/L of ISAV-SF resulted in noteworthy cardiac developmental aberrations. These anomalies encompassed enlarged pericardial area, diminished heart rate, alterations in SV-BA distance, and the detachment of cardiomyocytes from the endocardium. Exposure to ISAV-SF caused disruption of the expression of genes related to cardiac development (gata4, klf2a, nkx2.5, vmhc, tbx2b), especially in the high concentration group. Moreover, the Notch signaling pathway was inhibited and oxidative stress levels were upregulated in all exposed groups. Remarkably, the administration of the antioxidant astaxanthin effectively mitigated oxidative stress levels, thus ameliorating heart developmental impairments. These results suggest that ISAV-SF may contribute to cardiac developmental defects by upregulating oxidative stress. This study serves as a pivotal reference for the utilization of ISAV-SF within the market, emphasizing the necessity to curtail its introduction into aquatic environments during production and consumption and to evaluate its repercussions on aquatic organisms.

Isavuconazole Induces Neurodevelopment Defects and Motor Behaviour Impairment in Zebrafish Larvae

Isavuconazole is a broad-spectrum antifungal drug used for the treatment of serious infections caused by invasive aspergillosis and mucormycosis in adults. With the continuous use of this drug, its safety and environmental impact have received increasing attention. However, information on the adverse effects of the drug is very limited. Fish is a particularly important model for assessing environmental risks. In this study, the aquatic vertebrate zebrafish was used as a model to study the toxic effects and mechanisms of isavuconazole. We exposed zebrafish embryos to 0.25, 0.5, and 1 mg/L of isavuconazole 6 h after fertilization. The results showed that at 72 hpf, isavuconazole exposure reduced heart rate, body length, and survival of zebrafish embryos compared to controls. Secondly, when isavuconazole reached a certain dose level (0.25 mg/L), it caused morphological changes in the Tg(elavl3:eGFP) transgenic fish line, with the head shrunk, the body bent, the fluorescence intensity becoming weaker, the abnormal motor behaviour, etc. At the same time, exposure of zebrafish embryos to isavuconazole downregulated acetylcholinesterase (AchE) and adenosine triphosphate (ATPase) activities but upregulated oxidative stress, thereby disrupting neural development and gene expression of neurotransmitter pathways. In addition, astaxanthin partially rescued the neurodevelopmental defects of zebrafish embryos by downregulating oxidative stress. Thus, our study suggests that isavuconazole exposure may induce neurodevelopment defects and behavioural disturbances in larval zebrafish.

Beyond protein synthesis: non-translational functions of threonyl-tRNA synthetases

Aminoacyl-tRNA synthetases (AARSs) play an indispensable role in the translation of mRNAs into proteins. It has become amply clear that AARSs also have non-canonical or non-translational, yet essential, functions in a myriad of cellular and developmental processes. In this mini-review we discuss the current understanding of the roles of threonyl-tRNA synthetase (TARS) beyond protein synthesis and the underlying mechanisms. The two proteins in eukaryotes - cytoplasmic TARS1 and mitochondrial TARS2 - exert their non-canonical functions in the regulation of gene expression, cell signaling, angiogenesis, inflammatory responses, and tumorigenesis. The TARS proteins utilize a range of biochemical mechanisms, including assembly of a translation initiation complex, unexpected protein-protein interactions that lead to activation or inhibition of intracellular signaling pathways, and cytokine-like signaling through cell surface receptors in inflammation and angiogenesis. It is likely that new functions and novel mechanisms will continue to emerge for these multi-talented proteins.

Apatinib induces zebrafish hepatotoxicity by inhibiting Wnt signaling and accumulation of oxidative stress

Apatinib, a small-molecule VEGFR2-tyrosine kinase inhibitor, has shown potent anticancer activity in various clinical cancer treatments, but also different adverse reactions. Therefore, it is necessary to study its potential toxicity and working mechanism. We used zebrafish to investigate the effects of apatinib on the development of embryos. Zebrafish exposed to 2.5, 5, and 10 μM apatinib showed adverse effects such as decreased liver area, pericardial oedema, slow yolk absorption, bladder atrophy, and body length shortening. At the same time, it leads to abnormal liver tissue structure, liver function and related gene expression. Furthermore, after exposure to apatinib, oxidative stress levels were significantly elevated but liver developmental toxicity was effectively ameliorated with oxidative stress inhibitor treatment. Apatinib induces down-regulation of key target genes of Wnt signaling pathway in zebrafish, and it is found that Wnt activator can significantly rescue liver developmental defects. These results suggest that apatinib may induce zebrafish hepatotoxicity by inhibiting the Wnt signaling pathway and up-regulating oxidative stress, helping to strengthen our understanding of rational clinical application of apatinib.

Sphk1 deficiency induces apoptosis and developmental defects and premature death in zebrafish

The sphk1 gene plays a crucial role in cell growth and signal transduction. However, the developmental functions of the sphk1 gene during early vertebrate zebrafish embryo remain not completely understood. In this study, we constructed zebrafish sphk1 mutants through CRISPR/Cas9 to investigate its role in zebrafish embryonic development. Knockout of the sphk1 gene was found to cause abnormal development in zebrafish embryos, such as darkening and atrophy of the head, trunk deformities, pericardial edema, retarded yolk sac development, reduced heart rate, and premature death. The acetylcholinesterase activity was significantly increased after the knockout of sphk1, and some of the neurodevelopmental genes and neurotransmission system-related genes were expressed abnormally. The deletion of sphk1 led to abnormal expression of immune genes, as well as a significant decrease in the number of hematopoietic stem cells and neutrophils. The mRNA levels of cardiac development-related genes were significantly decreased. In addition, cell apoptosis increases in the sphk1 mutants, and the proliferation of head cells decreases. Therefore, our study has shown that the sphk1 is a key gene for zebrafish embryonic survival and regulation of organ development. It deepened our understanding of its physiological function. Our study lays the foundation for investigating the mechanism of the sphk1 gene in early zebrafish embryonic development.

Recessive aminoacyl-tRNA synthetase disorders: lessons learned from in vivo disease models

Protein synthesis is a fundamental process that underpins almost every aspect of cellular functioning. Intriguingly, despite their common function, recessive mutations in aminoacyl-tRNA synthetases (ARSs), the family of enzymes that pair tRNA molecules with amino acids prior to translation on the ribosome, cause a diverse range of multi-system disorders that affect specific groups of tissues. Neurological development is impaired in most ARS-associated disorders. In addition to central nervous system defects, diseases caused by recessive mutations in cytosolic ARSs commonly affect the liver and lungs. Patients with biallelic mutations in mitochondrial ARSs often present with encephalopathies, with variable involvement of peripheral systems. Many of these disorders cause severe disability, and as understanding of their pathogenesis is currently limited, there are no effective treatments available. To address this, accurate in vivo models for most of the recessive ARS diseases are urgently needed. Here, we discuss approaches that have been taken to model recessive ARS diseases in vivo, highlighting some of the challenges that have arisen in this process, as well as key results obtained from these models. Further development and refinement of animal models is essential to facilitate a better understanding of the pathophysiology underlying recessive ARS diseases, and ultimately to enable development and testing of effective therapies.

High expression of TARS is associated with poor prognosis of endometrial cancer

INTRODUCTION

Endometrial cancer is the second largest and most common cancer in the world. It is urgent to explore novel biomarkers.

METHODS

Data were obtained from The Cancer Genome Atlas (TCGA) database. The receiver operating characteristic (ROC) curves, Kaplan-Meier curves and Cox analysis, nomograms, gene set enrichment analysis (GSEA) were conducted. Cell proliferation experiments were performed in Ishikawa cell.

RESULTS

TARS was significantly highly expressed in serous type, G3 grade, and deceased status. Significant association was between high TARS expression with poor overall survival (P = 0.0012) and poor disease specific survival (P = 0.0034). Significant differences were observed in advanced stage, G3 and G4, and old. The stage, diabetes, histologic grade, and TARS expression showed independent prognostic value for overall survival of endometrial cancer. The stage, histologic grade, and TARS expression showed independent prognostic value for disease specific survival of endometrial cancer. Activated CD4⁺ T cell, effector memory CD4⁺ T cell, memory B cell and type 2 T helper cell may participate in the high TARS expression related immune response in endometrial cancer. The CCK-8 results showed significantly inhibited cell proliferation in si-TARS (P < 0.05) and promoted cell proliferation in O-TARS (P < 0.05), confirmed by the colony formation and live/dead staining.

CONCLUSION

High TARS expression was found in endometrial cancer with prognostic and predictive value. This study will provide new biomarker TARS for diagnosis and prognosis of endometrial cancer.

Exposure to pyrazosulfuron-ethyl induces immunotoxicity and behavioral abnormalities in zebrafish embryos

Pyrazosulfuron-ethyl is one of the most widely used herbicides in agriculture and can be widely detected in aquatic ecosystems. However, its biosafety, including its potential toxic effects on aquatic organisms and its mechanism, is still poorly understood. As an ideal vertebrate model, zebrafish, the effect of pyrazosulfuron-ethyl on early embryonic development and immunotoxicity of zebrafish can be well evaluated. From 10 to 72 h post fertilization (hpf), zebrafish embryos were exposed to 1, 5, and 9 mg/L pyrazosulfuron-ethyl which led in a substantial reduction in survival, total length, and heart rate, as well as a range of behavioral impairments. In zebrafish larvae, the number of neutrophils and macrophages was considerably decreased and oxidative stress levels increased in a dose-dependent way after pyrazosulfuron-ethyl exposure. And the expression of immune-related genes, such as TLR-4, MyD88 and IL-1β, were downregulated by pyrazosulfuron-ethyl exposure. Moreover, pyrazosulfuron-ethyl exposure also inhibited motor behavior. Notch signaling was upregulated after exposure to pyrazosulfuron-ethyl, while inhibition of Notch signaling pathway could rescue immunotoxicity. Therefore, our findings suggest that pyrazosulfuron-ethyl has the potential to induce immunotoxicity and neurobehavioral changes in zebrafish larvae.

Threonyl-tRNA synthetase gene, a potential target for RNAi-based control of three rice planthoppers

BACKGROUND

RNA interference (RNAi) has potential as a new strategy for pest control. However, the current overemphasis on the control of a single pest increased control costs. The aim of this study was to find a green method of controlling several pests without affecting the natural enemies with a single target gene. One possible RNAi target is the threonyl-tRNA synthetase (ThrRS), which is conserved and plays a significant role in protein biosynthesis.

RESULTS

In this study, one threonyl-tRNA synthetase gene (NlthrS) was identified from the brown planthopper (Nilaparvata lugens). Spatio-temporal expression pattern analysis showed that NlthrS was highly expressed in the ovary, late embryogenesis, nymphs and female adults. In addition, RNAi-mediated knockdown of NlthrS caused 85.6% nymph mortality, 100% female infertility, molting disorder, extended nymph duration and shortened adult longevity. Target-specific results were obtained when dsNlthrS was used to interfere with the whiteback planthopper (Sogatella furcifera), small brown planthopper (Laodelphax striatellus), zig-zag winged leafhopper (Inazuma dorsalis) and their natural enemy (green mirid bug, Cyrtorhinus lividipennis). In addition, dsNlthrS could cause high mortalities of three species of planthoppers (85.6-100%), while only dsNlthrS-1 led to the death (97.3%) of I. dorsalis that was not affected by dsNlthrS-2. Furthermore, neither dsNlthrS-1 nor dsNlthrS-2 could influence the survival of C. lividipennis.

CONCLUSION

The results reveal the biological functions of ThrRS in N. lugens in addtion to its protein synthesis, deepening our understanding of tRNA synthase in insects and providing a new method for the control of several rice pests via one dsRNA design. © 2022 Society of Chemical Industry.

Nrf2 dictates the neuronal survival and differentiation of embryonic zebrafish harboring compromised alanyl-tRNA synthetase

tRNA synthetase deficiency leads to unfolded protein responses in neuronal disorders; however, its function in embryonic neurogenesis remains unclear. This study identified an aars1cq71/cq71 mutant zebrafish allele that showed increased neuronal apoptosis and compromised neurogenesis. aars1 transcripts were highly expressed in primary neural progenitor cells, and their aberration resulted in protein overloading and activated Perk. nfe2l2b, a paralog of mammalian Nfe2l2, which encodes Nrf2, is a pivotal executor of Perk signaling that regulates neuronal phenotypes in aars1cq71/cq71 mutants. Interference of nfe2l2b in nfe2l2bΔ1/Δ1 mutants did not affect global larval development. However, aars1cq71/cq71;nfe2l2bΔ1/Δ1 mutant embryos exhibited increased neuronal cell survival and neurogenesis compared with their aars1cq71/cq71 siblings. nfe2l2b was harnessed by Perk at two levels. Its transcript was regulated by Chop, an implementer of Perk. It was also phosphorylated by Perk. Both pathways synergistically assured the nuclear functions of nfe2l2b to control cell survival by targeting p53. Our study extends the understanding of tRNA synthetase in neurogenesis and implies that Nrf2 is a cue to mitigate neurodegenerative pathogenesis.

Functional and pathologic association of aminoacyl-tRNA synthetases with cancer

Although key tumorigenic and tumor-suppressive factors have been unveiled over the last several decades, cancer remains the most life-threatening disease. Multiomic analyses of patient samples and an in-depth understanding of tumorigenic processes have rapidly revealed unexpected pathologic associations of new cellular factors previously overlooked in cancer biology. In this regard, the newly discovered activities of human aminoacyl-tRNA synthases (ARSs) deserve attention not only for their pathological significance in tumorigenesis but also regarding diagnostic and therapeutic implications. ARSs are not only essential enzymes covalently linking substrate amino acids to cognate tRNAs for protein synthesis but also function as regulators of cellular processes by sensing different cellular conditions. With their catalytic role in protein synthesis and their regulatory role in homeostasis, functional alterations or dysregulation of ARSs might be pathologically associated with tumorigenesis. This review focuses on the potential implications of ARS genes and proteins in different aspects of cancer based on various bioinformatic analyses and experimental data. We also review their diverse activities involving extracellular secretion, protein–protein interactions, and amino acid sensing, which are related to cancers. The newly discovered cancer-related activities of ARSs are expected to provide new opportunities for detecting, preventing and curing cancers.

Enzymes called aminoacyl-tRNA synthetases (ARSs), which play a central role in all life, are becoming implicated in several aspects of cancer in ways that may lead to new approaches for prevention, detection and treatment. ARS enzymes catalyse the ligation of amino acids to transfer RNA molecules to allow amino acids to combine in the correct sequences to form proteins. Jung Min Han, Sunghoon Kim and colleagues at Yonsei University, Incheon, South Korea, review researches implicating ARS enzymes and the genes that code for them in a variety of cancers. The behavior of ARS enzymes and their genes are found to be altered in several types of cancer cells in ways that may either initiate or support the onset and development of the disease, through which they could be suggested as targets for novel anti-cancer drugs.

Selective and competitive functions of the AAR and UPR pathways in stress-induced angiogenesis

The amino acid response (AAR) and unfolded protein response (UPR) pathways converge on eIF2α phosphorylation, which is catalyzed by Gcn2 and Perk, respectively, under different stresses. This close interconnection makes it difficult to specify different functions of AAR and UPR. Here, we generated a zebrafish model in which loss of threonyl-tRNA synthetase (Tars) induces angiogenesis dependent on Tars aminoacylation activity. Comparative transcriptome analysis of the tars-mutant and wild-type embryos with/without Gcn2- or Perk-inhibition reveals that only Gcn2-mediated AAR is activated in the tars-mutants, whereas Perk functions predominantly in normal development. Mechanistic analysis shows that, while a considerable amount of eIF2α is normally phosphorylated by Perk, the loss of Tars causes an accumulation of uncharged tRNA^Thr, which in turn activates Gcn2, leading to phosphorylation of an extra amount of eIF2α. The partial switchover of kinases for eIF2α largely overwhelms the functions of Perk in normal development. Interestingly, although inhibition of Gcn2 and Perk in this stress condition both can reduce the eIF2α phosphorylation levels, their functional consequences in the regulation of target genes and in the rescue of the angiogenic phenotypes are dramatically different. Indeed, genetic and pharmacological manipulations of these pathways validate that the Gcn2-mediated AAR, but not the Perk-mediated UPR, is required for tars-deficiency induced angiogenesis. Thus, the interconnected AAR and UPR pathways differentially regulate angiogenesis through selective functions and mutual competitions, reflecting the specificity and efficiency of multiple stress response pathways that evolve integrally to enable an organism to sense/respond precisely to various types of stresses.

Lenvatinib exposure induces hepatotoxicity in zebrafish via inhibiting Wnt signaling

Lenvatinib is a multi-kinase inhibitor for widely treating thyroid cancer. However, little studies have been done about it or its toxicity on embryonic development of vertebrate. In this study, we used zebrafish to assess the effect of lenvatinib on early embryonic development. Exposure of zebrafish embryos to 58, 117, 176 nM lenvatinib induced abnormal embryonic development, such as decreased heart rate, pericardial edema, delayed yolk absorption, and bladder atrophy. Lenvatinib exposure reduced liver area and down-regulated liver developmental related genes. The proliferation of hepatocytes and the expression of apoptosis-related genes were significantly reduced.by Lenvatinib. Furthermore, the imbalance of liver metabolism and abnormal liver tissue structure were observed in adult zebrafish after Lenvatinib exposure. Oxidative stress was up-regulated by lenvatinib and astaxanthin partially rescued hepatic developmental defects via downregulating oxidative stress. After lenvatinib exposure, Wnt signaling was down-regulated, and activation of Wnt signaling partially rescued hepatic developmental defects. Therefore, these results suggested that lenvatinib might induce zebrafish hepatotoxicity by down-regulating Wnt signaling related genes and inducing oxidative stress. This study provides a reference for the potential hepatotoxicity of lenvatinib during embryonic development and raises health concern about the potential harm of exposure to lenvatinib for foetuses.

The regulatory roles of aminoacyl-tRNA synthetase in cardiovascular disease

Aminoacyl-tRNA synthetases (ARSs) are widely found in organisms, which can activate amino acids and make them bind to tRNA through ester bond to form the corresponding aminoyl-tRNA. The classic function of ARS is to provide raw materials for protein biosynthesis. Recently, emerging evidence demonstrates that ARSs play critical roles in controlling inflammation, immune responses, and tumorigenesis as well as other important physiological and pathological processes. With the recent development of genome and exon sequencing technology, as well as the discovery of new clinical cases, ARSs have been reported to be closely associated with a variety of cardiovascular diseases (CVDs), particularly angiogenesis and cardiomyopathy. Intriguingly, aminoacylation was newly identified and reported to modify substrate proteins, thereby regulating protein activity and functions. Sensing the availability of intracellular amino acids is closely related to the regulation of a variety of cell physiology. In this review, we summarize the research progress on the mechanism of CVDs caused by abnormal ARS function and introduce the clinical phenotypes and characteristics of CVDs related to ARS dysfunction. We also highlight the potential roles of aminoacylation in CVDs. Finally, we discuss some of the limitations and challenges of present research. The current findings suggest the significant roles of ARSs involved in the progress of CVDs, which present the potential clinical values as novel diagnostic and therapeutic targets in CVD treatment.

Exposure to diclofop-methyl induces cardiac developmental toxicity in zebrafish embryos

Diclofop-methyl (DM) is one of the most widely used herbicides in agriculture production and has been frequently detected in both freshwater and environments, even agricultural products. However, the potential toxic effects of DM on organisms and the underlying mechanisms are still poorly understood. In this study, we utilized zebrafish to evaluate the toxicity of DM during the cardiovascular developmental process. Exposure of zebrafish embryos to 0.75, 1.0 and 1.25 mg/L DM induced cardiac defects, such as pericardial edema, slow heart rate and long SV-BA distance but the vascular development in zebrafish larvae was not influenced by DM treatment. The expression of cardiac-related genes were disordered and DM exposure initiated disordering cardiogenesis from the period of precardiac mesoderm formation. Moreover, the apoptosis and proliferation of cardiomyocytes were not influenced but the levels of oxidative stress were upregulated by DM exposure. Fullerenes and astaxanthin was able to rescue cardiac defects caused by DM via downregulating oxidative stress. Wnt signaling was downregulated after DM treatment and activation of Wnt signaling could rescue cardiac defects. Therefore, our results suggest that DM has the potential to induce cardiac developmental toxicity through upregulation of Wnt-Mediated (reactive oxygen species) ROS generation in zebrafish larvae.

Nanocurcumin Inhibits Angiogenesis via Down-regulating hif1a/VEGF-A Signaling in Zebrafish

BACKGROUND

Curcumin has anti-inflammatory, antioxidant and anticancer properties. Despite the considerable evidence showing that curcumin is an efficacious and safe compound for multiple medicinal benefits, there are some demerits with respect to the therapeutic effectiveness of curcumin, namely, poor stability and solubility, and its role in angiogenesis in vivo is still not yet clear. More recently, the biodegradable polymer nanoparticles have been developed. This offers promise for the therapeutic effectiveness of curcumin by increasing its bioavailability, solubility and retention time.

METHODS

Here, we compared the medicinal effectiveness of curcumin and nanocurcumin (NC), and found that nanocurcumin can inhibit angiogenesis more effectively than curcumin in zebrafish. Tests of proliferation and apoptosis showed no difference between nanocurcumin-treated and wildtype embryos.

RESULTS

qPCR and in situ hybridization experiments indicated that the VEGF signaling pathway genes, vegfa, VEGF-C and flt4 were all down-regulated after nanocurcumin treatment, and vegfa over-expression rescued the vascular defective phenotype. Moreover, hif1a expression also decreased and hif1a over-expression also rescued the vascular defective phenotype but the Notch signaling pathway had no difference after nanocurcumin treatment.

CONCLUSION

These results indicate that nano curcumin inhibits angiogenesis in zebrafish by downregulating hif1a/vegfa signaling pathway. Hence, our work reveals the key role of nanocurcumin in angiogenesis in vivo.

Exposure to diclofop-methyl induces immunotoxicity and behavioral abnormalities in zebrafish embryos

Diclofop-methyl (DM) is widely used in agriculture and may lead to serious toxicity. However, a limited number of studies have been performed to evaluate the toxicity of DM in the immune and nervous systems of animals. Here, we utilized a good vertebrate model, zebrafish, to evaluate the toxicity of DM during the developmental process. Exposure of zebrafish embryos to 0.1, 0.3 and 0.5 mg/l DM from 6 h post fertilization (hpf) to 72 hpf induced developmental abnormalities, such as shorter body lengths and yolk sac edemas. The number of immune cells in zebrafish larvae was significantly reduced, but the inflammatory response was not influenced by DM treatment. The expression of immune-related genes were downregulated and the levels of oxidative stress were upregulated by DM exposure. Moreover, locomotor behaviors were inhibited by DM exposure. Therefore, our results suggest that DM has the potential to induce immunotoxicity and cause behavioral changes in zebrafish larvae. This study provides new evidence of the influence of DM exposure on aquatic ecosystems.

Knock-Down of Histidyl-tRNA Synthetase Causes Cell Cycle Arrest and Apoptosis of Neuronal Progenitor Cells in vivo

Histidyl-tRNA Synthetase (HARS) is a member of the aminoacyl-tRNA synthetase family, which attach amino acids to their associated tRNA molecules. This reaction is a crucial step in protein synthesis that must be carried out in every cell of an organism. However, a number of tissue-specific, human genetic disorders have been associated with mutations in the genes for aminoacyl-tRNA synthetases, including HARS. These associations indicate that, while we know a great deal about the molecular and biochemical properties of this enzyme, we still do not fully understand how these proteins function in the context of an entire organism. To this end, we set out to knock-down HARS expression in the zebrafish and characterize the developmental consequences. Through our work we show that some tissues, particularly the nervous system, are more sensitive to HARS loss than others and we reveal a link between HARS and the proliferation and survival of neuronal progenitors during development.

Loss of Leucyl-tRNA synthetase b leads to ILFS1-like symptoms in zebrafish

Leucyl-tRNA synthetase (LARS) is a kind of aminoacyl-tRNA synthetases (aaRSs), which is important for protein synthesis. Following the discovery of three clinical cases which carry LARS mutations, it has been designated as the infantile liver failure syndrome type 1 (ILFS1) gene. ILFS1 is a kind of infantile hepatopathy, which is difficult to diagnose and manage. As the mechanism underlying this disease is poorly understood and LARS is conserved among vertebrates, we obtained zebrafish larsb^cq68 mutant via CRISPR/Cas9 technology to investigate the role of larsb in vivo. In mutant, the proliferation ability of liver was drastically decreased at later stages accompanied with severe DNA damage. Further studies demonstrated that the mTORC1 signaling was hyperactivated in larsb^cq68 mutant. Inhibition of mTORC1 signaling pathway by Rapamycin or mTORC1 morpholino can partially rescue the liver failure of the mutants. These data revealed that larsb mutation caused ILFS1-like phenotype in zebrafish, and indicated this mutant may serve as a potential model for ILFS1. Furthermore, we demonstrated that rapamycin treatment can partially rescue the liver defect in mutants, thus providing a practicable therapeutic plan for ILFS1.

A noncanonical function of histidyl-tRNA synthetase: inhibition of vascular hyperbranching during zebrafish development

Histidyl‐tRNA synthetase (Hars) catalyzes the ligation of histidine residues to cognate tRNA. Here, we demonstrate a noncanonical function of Hars in vascular development in zebrafish. We obtained a novel zebrafish cq34 mutant which exhibited hyperbranching of cranial and intersegmental blood vessels 48 h after fertilization. The gene responsible for this phenotype was identified as hars. We found the increased expression of cdh5 and vegfa in the hars^cq34 mutant. Knockdown of cdh5 in the mutant reduced disordered connections of the hindbrain capillaries. Inhibition of vascular endothelial growth factor signaling suppressed the abnormal vascular branching observed in the mutant. Moreover, the human HARSmRNA rescued the vascular defects in the cq34 mutant. Thus, the noncanonical function of Hars regulates vascular development, mainly by modulating expression of cdh5 and vegfa.

Ribosome biogenesis protein Urb2 regulates hematopoietic stem cells development via P53 pathway in zebrafish

Ribosome biogenesis is a significant process in cells. Dysfunction in this process will result in the defects of protein synthesis and consequently cause the development of specific diseases called ribosomopathies. Mutations in ribosome biogenesis protein Rps19, Rpl5, or Rpl11 can lead to hematopoietic defects in human, thus triggering the disease Diamond Blackfan anemia. However, the regulatory mechanisms of ribosome biogenesis in hematopoiesis remain incompletely understood. In this study, we describe a zebrafish mutant cq42, which carries a nonsense mutation in the gene that encodes ribosome biogenesis 2 homolog (Urb2). Urb2 is strongly expressed in the caudal hematopoietic tissue (CHT) during hematopoietic stem cells (HSCs) expanding. Molecular characterization of urb2^cq42 larvae suggest that urb2 deficiency notably decrease the population of HSCs in CHT and early T cells in thymus. Further analysis shows that compromised cell proliferation and superfluous apoptosis are observed in the CHT of urb2^cq42 mutant. P53 pathway is upregulated in the urb2^cq42 larvae and loss-of-function of P53 can fully rescue the hematopoietic defects in urb2^cq42 mutant. These data demonstrate that urb2 is essential for HSCs development through the regulation of P53 pathway.

Cytosolic aminoacyl-tRNA synthetases: Unanticipated relocations for unexpected functions

Prokaryotic and eukaryotic cytosolic aminoacyl-tRNA synthetases (aaRSs) are essentially known for their conventional function of generating the full set of aminoacyl-tRNA species that are needed to incorporate each organism's repertoire of genetically-encoded amino acids during ribosomal translation of messenger RNAs. However, bacterial and eukaryotic cytosolic aaRSs have been shown to exhibit other essential nonconventional functions. Here we review all the subcellular compartments that prokaryotic and eukaryotic cytosolic aaRSs can reach to exert either a conventional or nontranslational role. We describe the physiological and stress conditions, the mechanisms and the signaling pathways that trigger their relocation and the new functions associated with these relocating cytosolic aaRS. Finally, given that these relocating pools of cytosolic aaRSs participate to a wide range of cellular pathways beyond translation, but equally important for cellular homeostasis, we mention some of the pathologies and diseases associated with the dis-regulation or malfunctioning of these nontranslational functions.