Analysis of vascular disruption in zebrafish embryos as an endpoint to predict developmental toxicity

Transgenic zebrafish embryos to evaluate the in vivo effects of different liposome-paclitaxel nanocarrier system

Zebrafish is an established valuable model for understanding the complex in vivo behavior of systemic nanocarrier strategies, their safety profile, and the array of possible compositions. To date, we have explored the possibility of Paclitaxel (PTX) delivery using liposome systems as a promising approach to treating cancer. Despite its benefits, this efficacious anti-cancer drug presents a main adverse effect, such as the onset of chemotherapy-induced peripheral neuropathy (CIPN). Thus, many research efforts are aimed at searching for the resolution or reduction of such problems. Taking advantage of zebrafish embryos, a powerful model for predicting and translating what is observed in humans, we investigated the plain PTX outcomes and compared them to the effects of different liposomes loaded with PTX. Since approximately 70% of human genes have at least one orthologue in zebrafish, studying the molecular mechanisms underlying chemotherapy-induced toxicity and increased oxidative stress becomes easy. First, we used a transgenic model to evaluate the systemic response to different concentrations of PTX, planning the final concentration to be loaded in liposomes, with and without functionalization. Then, we assessed the effects of this promising nanocarrier system at a molecular, histochemical, and behavioral level in reducing the detrimental side effects of the most successful cancer drug.

High-content screening (HCS) workflows for FAIR image data management with OMERO

High-content screening (HCS) for bioimaging is a powerful approach to studying biological processes, enabling the acquisition of large amounts of images from biological samples. However, it generates massive amounts of metadata, making HCS experiments a unique data management challenge. This data includes images, reagents, protocols, analytic outputs, and phenotypes, all of which must be stored, linked, and made accessible to users, scientists, collaborators, and the broader community to ensure sharable results. This study showcases different approaches using Workflow Management Systems (WMS) to create reusable semi-automatic workflows for HCS bioimaging data management, leveraging the image data management platform OMERO. The three developed workflows demonstrate the transition from a local file-based storage system to an automated and agile image data management framework. These workflows facilitate the management of large amounts of data, reduce the risk of human error, and improve the efficiency and effectiveness of image data management. We illustrate how applying WMS to HCS data management enables us to consistently transfer images across different locations in a structured and reproducible manner, reducing the risk of errors and increasing data consistency and reproducibility. Furthermore, we suggest future research direction, including developing new workflows and integrating machine learning algorithms for automated image analysis. This study provides a blueprint for developing efficient and effective image data management systems for HCS experiments and demonstrates how different WMS approaches can be applied to create reusable, semi-automated workflows for HCS bioimaging data management using OMERO.

Integrative toxicity assessment of tocotrienol-rich fraction from palm oil using in silico methods and zebrafish embryotoxicity model

Tocotrienol-rich fraction (TRF), a natural form of vitamin E derived from palm oil, possesses antioxidant properties. However, its potential embryonic developmental toxicity remains unclear. This study investigated TRF's toxicity using in silico methods and zebrafish embryos. Zebrafish embryos were exposed to TRF (31.25 to 2000 μg/mL) for 96 h post-fertilization (hpf). Mortality, hatching rate, heart rate, and morphological malformations were assessed at 24, 48, 72, and 96 hpf. In silico analysis predicted good pharmacokinetic properties and minimal side effects for five TRF constituents, except for hERG II inhibition, which is associated with cardiac toxicity. TRF exposure up to 96 hpf showed no embryotoxicity in zebrafish at ≤1000 μg/mL. However, TRF at concentrations of ≥1000 μg/mL significantly inhibited hatching rate at 72 hpf, indicating a delay in the hatching process. Additionally, 1000 μg/mL of TRF resulted in reduced heart rate and hypopigmentation in the embryos. Moreover, higher TRF concentrations (≥500 μg/mL) caused morphological malformations including spinal curvature, pericardial edema, and yolk sac edema, in the embryos. These findings suggest that TRF from palm oil is likely safe at concentrations below 500 μg/mL during embryonic development. However, the potential effects of long-term exposure and chronic toxicity warrant further investigation to ensure safety during early pregnancy.

Dynamics in zebrafish development define transcriptomic specificity after angiogenesis inhibitor exposure

Testing for developmental toxicity is an integral part of chemical regulations. The applied tests are laborious and costly and require a large number of vertebrate test animals. To reduce animal numbers and associated costs, the zebrafish embryo was proposed as an alternative model. In this study, we investigated the potential of transcriptome analysis in the zebrafish embryo model to support the identification of potential biomarkers for key events in developmental toxicity, using the inhibition of angiogenesis as a proof of principle. Therefore, the effects on the zebrafish transcriptome after exposure to the tyrosine kinase inhibitors, sorafenib (1.3 µM and 2.4 µM) and SU4312 (1 µM, 2 µM, and 5 µM), and the putative vascular disruptor compound rotenone (25 nM and 50 nM) were analyzed. An early (2 hpf-hours post fertilization) and a late (24 hpf) exposure start with a time resolved transcriptome analysis was performed to compare the specificity and sensitivity of the responses with respect to anti-angiogenesis. We also showed that toxicodynamic responses were related to the course of the internal concentrations. To identify differentially expressed genes (DEGs) the time series data were compared by applying generalized additive models (GAMs). We observed mainly unspecific developmental toxicity in the early exposure scenario, while a specific repression of vascular related genes was only partially observed. In contrast, differential expression of vascular-related genes could be identified clearly in the late exposure scenario. Rotenone did not show angiogenesis-specific response on a transcriptomic level, indicating that the observed mild phenotype of angiogenesis inhibition may represent a secondary effect.

Leveraging Zebrafish Embryo Phenotypic Observations to Advance Data-Driven Analyses in Toxicology

Zebrafish have emerged as a central model organism in toxicological research. Zebrafish embryos are exempt from certain animal testing regulations, which facilitates their use in toxicological testing. Next to the zebrafish embryo acute toxicity test (ZFET) according to the OECD TG 236, fish embryos are used in mechanistic investigations, chemical screenings, ecotoxicology, and drug development. However, inconsistencies in the applied test protocols and the monitored endpoints in addition to a lack of standardized data formats impede comprehensive meta-analyses and cross-study comparisons. To address these challenges, we developed the Integrated Effect Database for Toxicological Observations (INTOB), a comprehensive data management tool that standardizes the collection of metadata and phenotypic observations using a controlled vocabulary. By incorporating data from more than 600 experiments into the database and subsequent comprehensive data analyses, we demonstrate its utility in improving the comparability and interoperability of toxicity data. Our results show that the ZFET can detect toxicity spanning 7 orders of magnitude at the scale of effect concentrations. We also highlight the potential of read-across analyses based on morphological fingerprints and their connection to chemical modes of action, provide information on control variability of the ZFET, and highlight the importance of time for mechanistic understanding in chemical exposure-effect assessments. We provide the full Findable, Accessible, Interoperable, and Reusable (FAIR) data set as well as the analysis workflow and demonstrate how professional data management, as enabled with INTOB, marks a significant advancement by offering a comprehensive framework for the systematic use of zebrafish embryo toxicity data, thus paving the way for more reliable, data-driven chemical risk assessment.

Effects of Valproic Acid Embryonic Exposure on Zebrafish: A Systematic Review and Meta-Analysis

Exposure to valproic acid (VPA) during embryogenesis has become a valuable tool for modeling neurodevelopmental disorders in animal models such as zebrafish (Danio rerio). This article examines the effects of embryonic exposure to VPA in zebrafish on the basis of 39 articles sourced from PubMed and Google Scholar. We conducted a systematic review and meta-analysis to elucidate the common impacts of VPA exposure and reported that VPA significantly altered development at various levels. Behaviorally, zebrafish exposed to VPA exhibit notable changes in their social interaction patterns. Physiologically, VPA exposure leads to significant alterations, including decreased heart rates, increased mortality rates, and pronounced morphological abnormalities. Pharmacological exposure has been linked to neuroanatomical and neurochemical changes. At the genetic level, VPA exposure is associated with the differential expression of genes involved in neurodevelopment and neuronal function. The synthesized data from these studies underscore the utility of zebrafish as a model organism for investigating the effects of teratogen exposure on neurodevelopment.

Applications of Zebrafish Embryo Models to Predict Developmental Toxicity for Agrochemical Product Development

The development of safe crop protection products is a complex process that traditionally relies on intensive animal use for hazard identification. Methods that capture toxicity in early stages of agrochemical discovery programs enable a more efficient and sustainable product development pipeline. Here, we explored whether the zebrafish model can be leveraged to identify mammalian-relevant toxicity. We used transgenic zebrafish to assess developmental toxicity following exposures to known mammalian teratogens and captured larval morphological malformations, including bone and vascular perturbations. We further applied toxicogenomics to identify common biomarker signatures of teratogen exposure. The results show that the larval malformation assay predicted teratogenicity with 82.35% accuracy, 87.50% specificity, and 77.78% sensitivity. Similar and slightly lower accuracies were obtained with the vascular and bone assays, respectively. A set of 20 biomarkers were identified that efficiently segregated teratogenic chemicals from nonteratogens. In conclusion, zebrafish are valuable, robust, and cost-effective models for toxicity testing in the early stages of product development.

A practical guide to bioimaging research data management in core facilities

Bioimage data are generated in diverse research fields throughout the life and biomedical sciences. Its potential for advancing scientific progress via modern, data-driven discovery approaches reaches beyond disciplinary borders. To fully exploit this potential, it is necessary to make bioimaging data, in general, multidimensional microscopy images and image series, FAIR, that is, findable, accessible, interoperable and reusable. These FAIR principles for research data management are now widely accepted in the scientific community and have been adopted by funding agencies, policymakers and publishers. To remain competitive and at the forefront of research, implementing the FAIR principles into daily routines is an essential but challenging task for researchers and research infrastructures. Imaging core facilities, well-established providers of access to imaging equipment and expertise, are in an excellent position to lead this transformation in bioimaging research data management. They are positioned at the intersection of research groups, IT infrastructure providers, the institution´s administration, and microscope vendors. In the frame of German BioImaging - Society for Microscopy and Image Analysis (GerBI-GMB), cross-institutional working groups and third-party funded projects were initiated in recent years to advance the bioimaging community's capability and capacity for FAIR bioimage data management. Here, we provide an imaging-core-facility-centric perspective outlining the experience and current strategies in Germany to facilitate the practical adoption of the FAIR principles closely aligned with the international bioimaging community. We highlight which tools and services are ready to be implemented and what the future directions for FAIR bioimage data have to offer.

Molecular signatures of angiogenesis inhibitors: a single-embryo untargeted metabolomics approach in zebrafish

Angiogenesis is a key process in embryonic development, a disruption of this process can lead to severe developmental defects, such as limb malformations. The identification of molecular perturbations representative of antiangiogenesis in zebrafish embryo (ZFE) may guide the assessment of developmental toxicity from an endpoint- to a mechanism-based approach, thereby improving the extrapolation of findings to humans. Thus, the aim of the study was to discover molecular changes characteristic of antiangiogenesis and developmental toxicity. We exposed ZFEs to two antiangiogenic drugs (SU4312, sorafenib) and two developmental toxicants (methotrexate, rotenone) with putative antiangiogenic action. Molecular changes were measured by performing untargeted metabolomics in single embryos. The metabolome response was accompanied by the occurrence of morphological alterations. Two distinct metabolic effect patterns were observed. The first pattern comprised common effects of two specific angiogenesis inhibitors and the known teratogen methotrexate, strongly suggesting a shared mode of action of antiangiogenesis and developmental toxicity. The second pattern involved joint effects of methotrexate and rotenone, likely related to disturbances in energy metabolism. The metabolites of the first pattern, such as phosphatidylserines, pterines, retinol, or coenzyme Q precursors, represented potential links to antiangiogenesis and related developmental toxicity. The metabolic effect pattern can contribute to biomarker identification for a mechanism-based toxicological testing.