Search Results (575)

For thousands of years, medicinal plants and their constituents have been used, mostly empirically/ethnopharmacologically, to cure patients with central nervous system (CNS) disorders. Anxiolytics derived from natural products (NPs) often share similar mechanisms of action to synthetic ones (e.g., benzodiazepines, BDZs). Although typically as effective as synthetic anxiolytics, NPs are considered to be devoid of the serious side effects linked to the use of BDZs. 8-Methoxypeucedanin (8-MP) is a rare furanocoumarin present in the fruits of Peucedanum luxurians Tamamsch. (Apiaceae). The primary objective of the presented study was to assess the anxiolytic activity of 8-MP using a zebrafish (Danio rerio) model of anxiety. Danio rerio larvae at 5 days post-fertilization (dpf) were used, with reversed thigmotaxis considered as an index of the anxiolytic activity. In addition to the behavioral study, qPCR analyses were performed to assess the role of 8-MP in modulating the expression of c-fos and bdnf, two key genes involved in neural activity. As evidenced by the behavioral study, 8-MP (1.5–15 µM) exhibited a significant influence on anxiety, with a U-shape dose–response effect. Moreover, the expression of c-fos and bdnf genes was significantly downregulated, providing novel insights into the mechanisms of action of the tested furanocoumarin. Full article

TAAR1 agonists have emerged as promising therapeutic agents capable of modulating glucose homeostasis, enhancing insulin secretion and suppressing appetite, making them attractive candidates for the treatment of obesity and related metabolic disorders. Despite their potential, the number of TAAR1-targeting compounds with well-defined pharmacological profiles remains limited. In this study, we identified and characterized JP-14, a novel aminoguanidine-based TAAR1 agonist, in a comprehensive panel of pharmacological assays. JP-14 promoted glucose uptake in HepG2 cells and reduced lipid deposition during 3T3-L1 adipocyte differentiation, with both actions dependent on TAAR1 signaling. In differentiated 3T3-L1 adipocytes, JP-14 reduced intracellular levels of both neutral lipids and phospholipids, indicating dual anti-steatotic and anti-phospholipidotic activity. In zebrafish larvae, toxicity profiling confirmed 10 µg/mL as a safe concentration for further in vivo studies. These assays showed that JP-14 promoted lipid mobilization and partially prevented fructose-induced lipid accumulation, demonstrating systemic metabolic benefits in vivo. Moreover, JP-14 markedly delayed gastric emptying in mice, an effect similar to loperamide and reversed by TAAR1 antagonism, supporting its role in regulating satiety and energy balance. Collectively, our findings establish JP-14 as a safe and metabolically active TAAR1 agonist with multifaceted effects on glucose and lipid metabolism. JP-14 represents a valuable pharmacological tool for probing TAAR1-mediated mechanisms in metabolic regulation. Full article

The Zebrafish Embryo Developmental Toxicity Assay (ZEDTA) is a promising and innovative method with potential to replace the screening of teratogenic substances in mammals during preclinical development. However, a harmonized and validated protocol does not exist for the ZEDTA, and data on the background incidence of spontaneous malformations are not readily accessible. Therefore, the aim of this research was twofold: (1) to optimize the ZEDTA protocol and (2) to generate historical control data. The most optimal results were achieved by exposing zebrafish larvae in 24-well plates at a temperature of 26 °C in combination with the renewal of test solutions after 48 h of exposure. Furthermore, the use of 0.5% v/v DMSO did not induce more malformations or mortality than exposure to standard ISO medium. In total, 26 valid experiments were conducted using the optimized ZEDTA protocol. An overall mortality of 3.5% was recorded after 96 h of exposure. Malformations were observed in 7.6% of all surviving larvae. The most frequently observed abnormalities included yolk sac deformation (4.0%), followed by tail (2.8%), heart (2.6%), and head malformations (1.6%). The optimized protocol was considered effective in supporting an optimal development rate of exposed zebrafish larvae, with low mortality and minimal background malformations. These findings indicate a low level of confounding factors and high reliability of results, making an essential step in the refinement of ZEDTA toward global harmonization and regulatory acceptance. Full article

This study presents nanofractionation analytics coupled with in vivo profiling of zebrafish embryo paralysis and lethality in response to toxins in cone snail venoms. The focus of this study is on the development of this approach using venoms of Conus marmoreus, Conus ebraeus, and Conus bandanus. In brief, cone snail venoms were separated using reversed-phase chromatography following high-resolution nanofractionation on microplates with parallel mass spectrometry, enabled via a post-column flow split. All collected fractions were dried overnight, followed by assays on zebrafish embryos. For the paralysis assessment, we monitored swimming behavior and swimming distance and found that exposure to cone snail toxins led to paralysis and decreased movement and swim distance. To correlate the masses of eluted toxins with their paralyzing effects and potency, we compared the fractionation retention time versus normalized swimming distance. This allowed identification of the masses of toxins with paralyzing bioactivity, which were predominantly conopeptides. To assess lethality, zebrafish embryos were exposed to fractionated toxins for 24 h, after which they were inspected. The lethal doses and correlated toxins were identified by comparing retention times of fractionation versus the lethal dose values calculated for each fraction. We found that the most lethal venom was from C. bandanus, displaying the largest number of lethal peptides, followed by C. marmoreus and C. ebraeus. On the other hand, the most paralytic venom was from C. ebraeus, presenting a higher number of peptides with non-lethal paralytic effects, followed by C. bandanus and C. marmoreus. This study provides a pipeline to rapidly identify paralytic and lethal cone snail venom toxins using the zebrafish embryo model. Full article

2-(Methylthio) benzothiazole (MTBT) is widely used in the industrial and pharmaceutical fields, but limited research has been conducted on its aquatic toxicity. In this study, we established a zebrafish model to systematically evaluate its developmental and functional toxicity, focusing on the cardiovascular systems of larvae. The results showed that MTBT significantly reduced heart rate, caused pericardial edema and deformity, delayed cardiac maturation, decreased stroke volume and cardiac output, and led to vascular structural defects. Mechanistically, MTBT upregulated the expression of the core target PTGS2, activated the apoptotic pathway, and mediated cardiovascular toxicity. This study is the first to systematically confirm the cardiovascular toxicity of MTBT, supplementing its toxicological database and providing a scientific basis for the establishment of environmental safety thresholds and risk management. Full article

The aim of our study was to make one step further to verify a method that can turn back mycotoxin-contaminated crops into the circular economy. Thus, the possibility of utilizing aflatoxin B1 (AfB1)-contaminated corn by yellow mealworms (Tenebrio molitor) was investigated to be used as fish feed components. Four different self-contaminated corn samples were used in our study, of which one was below and three were above the threshold limit (20 µg/kg) regulated by the European Union. The highest applied AfB1 concentration in our study for insect feeding was 415 µg/kg (more than twenty times higher than the threshold). After a five-week feeding period insect mortality was not increased, even in the highly contaminated group, compared to the negative control. The mycotoxin in the dried and ground insects was only detected in the case of feeding with the highest-concentration corn, however it remained as low as 2.2 µg/kg. For studying the possible physiology effects, insect grounds were used in feeding experiments of common carp (Cyprinus carpio) fries. Results showed that insect meal, even if originated from a highly mycotoxin-contaminated crop, did not have a significant effect on the examined fish fries, compared with the control groups. The AfB1 concentrations of the leftover frass after insect rearing were also measured, and in the case of the highest concentration mealworm group, it was 157.6 µg/kg (other groups were under 20 µg/kg). Toxicity of frass extracts from different contaminated groups was also studied using microinjected zebrafish (Danio rerio) embryos. Extracts of the highly contaminated frass samples caused 91.67 ± 3.33% mortality and led to numerous phenotypic changes, which highlights the need for responsible usage of the by-product. However, the effects of injected frass samples, originating from corn with lower and more environmentally relevant AfB1 concentrations, were significantly lower. Full article

EZH2, the catalytic subunit of polycomb repressive complex 2 (PRC2), plays a critical role in neural development by regulating gene expression through the trimethylation of lysine 27 on histone H3 (H3K27me3), which promotes chromatin remodeling and transcriptional repression. Although PRC2 is known to regulate cell fate specification and gliogenesis, its in vivo functions during vertebrate neurodevelopment, particularly at the level of neuronal subtype differentiation, remain incompletely understood. Here, we investigated the consequences of ezh2 loss-of-function during zebrafish brain development, focusing on oligodendrocyte differentiation, cerebellar neurogenesis, and the formation of neurotransmitter-specific neuronal populations. Using whole-mount in situ hybridization, we found that ezh2 inactivation does not alter the expression of oligodendrocyte lineage markers, indicating that early oligodendrocyte precursor cell specification and myelination are preserved. However, a significant reduction in cerebellar proliferation was observed in ezh2-deficient larvae, as evidenced by the downregulation of pcna and cyclin A2, while other brain regions remained unaffected. Notably, the expression of atoh1c, a key marker of glutamatergic cerebellar progenitors, was strongly reduced at 5 days post fertilization, suggesting a selective role for ezh2 in maintaining cerebellar progenitor identity. This was associated with impaired differentiation of both glutamatergic granule cells and GABAergic Purkinje cells in specific cerebellar subregions. In contrast, the expression of markers for other major neurotransmitter systems remained unaffected, indicating a region-specific requirement for ezh2 in neuronal development. Finally, behavioral analysis revealed a hyperlocomotor phenotype in ezh2^−/− larvae, consistent with cerebellar dysfunction. Together, these findings identify ezh2 as a key regulator of progenitor maintenance and neuronal differentiation in the cerebellum, highlighting its crucial role in establishing functional cerebellar circuits. Full article

Octominin is a peptide derived from the Octopus minor defense protein, which has shown antimicrobial and immunomodulatory properties. The present study describes the efficacy of Octominin-encapsulated chitosan (CN) nanoparticles (Octominin-CNPs) on in vitro and dermal wound healing in zebrafish. Initial viability analysis revealed there was no significant toxicity of Octominin-CNPs up to 200 μg/mL in human dermal fibroblast (HDF) cells and in zebrafish larvae (up to 50 μg/mL). Moreover, the potential wound healing activity of Octominin-CNPs was observed using the cell-scratch assay. In the in vivo study, wounded adult zebrafish were applied with the appropriate treatment (PBS, CNPs, Octominin, and Octominin-CNPs) 20 μg/wound/fish as a topical application at 0, 2, and 4 days post-wounding (dpw) while photographs of each wound site were taken at 2, 4, 7, 10, 14, and 21 dpw, and surface area was measured using ImageJ software (Ver. 1.8.0, NIH, Bethesda, MD, USA) to calculate the wound healing percentage (WHP) and wound healing rate (WHR). From the observed results, at 4 dpw, all treatments showed a negative impact on wound healing, where the lowest WHR and the WHP were given by the negative control (NC) until the 14th day. After 7 dpw, all fish except the NC showed increased wound healing activity. Compared to the Octominin, the Octominin-CNPs showed higher activity, which was at its peak on 21 dpw. Furthermore, Octominin-CNPs suppressed the expression of pro-inflammatory cytokine and chemokine mRNA expression with increased wound healing efficacy, and tissue repair compared to the Octominin-alone-treated fish at 7 dpw. Together, the observed results give insights into the use of nanoencapsulation as a means of drug delivery, especially for small peptides. Full article

Perfluorooctane sulfonamide (PFOSA), the direct precursor to perfluorooctane sulfonate (PFOS), is widely present in the environment. Research has indicated that PFOSA is cardiotoxic and hepatotoxic, but its impact on neurodevelopment remains unclear. In the current study, we observed that exposure of PFOSA caused neurodevelopmental toxicity in zebrafish embryos in a dose-dependent manner, as evidenced by impaired motor abilities and decreased swimming distance. We then demonstrated that PFOSA exposure downregulated the mRNA expression of neurodevelopment-related genes including a1-tubulin, elavl3, ache and dat. Moreover, PFOSA exposure resulted in dose-dependent oxidative stress, which triggers apoptosis in the brains of zebrafish larvae. We further showed that inhibition of the aryl hydrocarbon receptor (AhR) alleviated the oxidative stress and apoptosis induced by PFOSA, thereby counteracting the neurodevelopmental abnormalities in zebrafish larvae. In conclusion, these findings indicate PFOSA causes neurodevelopmental disorders by inducing oxidative stress and apoptosis through the AhR pathway. Full article

The potential hazards of triazole fungicides to non-target organisms necessitate environmental risk assessment. This study, therefore, focused on characterizing the differential toxicity of the enantiomers of Ipfentrifluconazole (IFZ), a new triazole fungicide, in zebrafish larvae using a multi-endpoint approach. Acute toxicity tests determined the LC₅₀ values of 1.709 mg/L for rac-IFZ, 1.531 mg/L for (+)-IFZ, and 1.809 mg/L for (−)-IFZ, indicating a higher toxicity of the (+)-enantiomer. To avoid overt mortality while revealing organ-level effects, we chose a concentration of approximately 20% of the LC50 of (+)-IFZ, which is 340 μg/L, as the exposure concentration. Exposure to IFZ induced developmental defects, including swim bladder malformation, cardiac blood pooling, and metabolic disturbances during the early developmental stage of zebrafish. Additionally, cardiac and hepatic development and function were disrupted in zebrafish larvae following IFZ exposure. Biochemical and transcriptomic analyses revealed distinct toxic mechanisms: (+)-IFZ primarily disrupted lipid metabolism through alterations in PPAR signaling pathway and fatty acid degradation, while (−)-IFZ significantly impaired cardiac function by affecting adrenergic signaling in cardiomyocytes and cardiac muscle contraction. Rac-IFZ mainly influenced drug metabolism, particularly cytochrome P450-related pathways. These findings demonstrated the toxic effects of IFZ, emphasizing the need for evaluating environmental and health risks of chiral pesticides. The study provides valuable insights into the molecular mechanisms underlying IFZ toxicity. Full article

Freshwater pollution is a global issue that can impact aquatic organisms in multiple ways. One of the many detrimental consequences of freshwater pollution is the disruption of the intestinal microbiome in aquatic animals. This review addresses the impact of various chemical entities like pesticides, heavy metals, antibiotics, dyes, and microplastic. Gut microbiota serves as a crucial regulator of metabolic processes across all organisms. Since numerous metabolic pathways are coordinated by microbial communities, even minor disruptions can lead to consequences ranging from mild to severe. The widespread use of chemicals in modern life has made them a primary focus of current gut microbiota research. Zebrafish (Danio rerio) can serve as a model organism to investigate gut microbiome responses to exposure to hazardous contaminants. In this review we include research studying pesticides (methomyl, λ-cyhalothrin, cyproconazole, dieldrin, penthiopyrad, acetochlor, metamifop, imidacloprid, difenoconazole, imazalil, cypermethrin), heavy metals (lead, cadmium, arsenic, chromium, copper, and various nanoparticles), antibiotics (oxytetracycline, florfenicol, doxycycline, trimethoprim, erythromycin, streptomycin, tetracycline, sulfamethoxazole, and clarithromycin), and microplastics (polystyrene, polyethylene, polyester, polypropylene). This review study provides a description of microbiome alterations due to single and combined short- and long-term exposure to the aforementioned contaminants in zebrafish and larvae microbiomes. Full article

Identifying reliable negative control compounds is essential for determining the sensitivity and specificity of screening assays. However, well-characterized negative controls for developmental neurotoxicity behavioral assays in larval zebrafish (Danio rerio) are lacking. This study evaluated nine chemicals with no reported evidence of mammalian developmental neurotoxicity, and a positive control (fluoxetine) for developmental and neurodevelopmental (i.e., behavioral) toxicity in zebrafish. Embryos were exposed to each chemical (≤100 µM) during development, 0–5 days post-fertilization (dpf), then assessed as larvae (6 dpf) using a locomotor behavior light–dark transition test. Behavior was analyzed using two methods: (1) the traditional method, comparing the average total distance moved, and (2) a 13-endpoint approach analyzing 13 aspects of the locomotor profile. Results showed that ibuprofen, omeprazole, and fluoxetine induced developmental toxicity (teratogenesis), with fluoxetine also causing behavioral neurotoxicity. Behavioral effects of developmental exposure to selegiline hydrochloride depended on the analysis method. Exposure to the other six chemicals (D-mannitol, glycerol, L-ascorbic acid, metformin hydrochloride, saccharin, and sodium benzoate), as well as ibuprofen or omeprazole, did not produce behavioral effects using either analysis method. Identifying negative control chemicals is essential for evaluating behavioral alterations precipitated by unknown substances and will assist with screening new chemicals for neurodevelopmental toxicity. Full article

Peach (Prunus persica) leaves, usually discarded in traditional Chinese medicine, were explored as a source of laxative agents. Using zebrafish larvae for bioactivity-guided fractionation, we isolated a single active flavanone that was identified by NMR and HR-MS as Sakuranetin. In vivo assays demonstrated that Sakuranetin (10–25 µM) accelerated intestinal transit in a dose-dependent fashion; at 25 µM, 64.8% of the fluorescent intestinal content was expelled. Untargeted LC-MS metabolomic analysis revealed significant perturbations in serine biosynthesis and N-glycan precursor biosynthesis, suggesting energetic rewiring of enterocytes. RNA-Seq analysis highlighted gnat1 as the most responsive gene, and molecular docking predicted a stable Sakuranetin–Gnat1 complex with a binding free energy of −8.7 kcal/mol. Concurrent down-regulation of rho transcripts indicated suppression of inflammatory signaling that often accompanies constipation. Our findings identified Sakuranetin as a potent promoter of gut motility and position the otherwise wasted peach leaves as an untapped botanical resource for developing anti-constipation therapeutics. Full article

Background/Objectives: Perturbation in terminal N-glycan processing is a feature of congenital disorders of glycosylation and neurological disorders. Since treatment options are limited, N-glycans are plausible therapeutic targets. Here, we investigated the consequences of substituting complex/hybrid with oligomannose types of N-glycans on nervous and musculature systems, employing mgat1a and mgat1b mutant zebrafish models. Methods: CRISPR Cas9 technology was employed to engineer the mgat1a zebrafish model. The N-glycan populations in Wt AB, mgat1a−/− and mgat1b−/− zebrafish were characterized via lectin blotting. Motor and sensory functions were measured by tail-coiling and touch-evoked response assays in embryos and larvae. Swimming locomotion and anxiety-like behavior were characterized in adult Wt AB, and mutant zebrafish using motility and novel tank dive assays. Results: The mgat1a−/− model had increased oligomannosylated proteins compared to Wt AB in embryos and dissected brain, spinal cord, skeletal muscle, heart, swim bladder, and skin from adults, supporting a global knockdown of GnT-I activity. Higher levels were also observed in mgat1a−/− relative to mgat1b−/−, except in the brain. Band patterns for oligomannosylated proteins were different between all three zebrafish lines. The mgat1−/− embryos and larvae had deficient motor and sensory functions which persisted into adulthood, with a higher deficiency in mgat1b−/−. Anxiety-like behavior was decreased and increased in adult mgat1a−/− and mgat1b−/−, respectively, compared to Wt AB. Conclusions: Taken together, this study revealed that aberrant terminal N-glycan processing impacts brain, spinal and muscle control, and hence will enhance our understanding of the vital role of complex/hybrid N-glycans in nervous system health. Full article

Tetramethyl bisphenol A (TMBPA), a novel alternative to Bisphenol A, is widely used as an industrial flame retardant and a raw material for tetramethyl polycarbonate plastics. With the increasing use of TMBPA, its aquatic ecological risks remain unclear. Therefore, this study investigated the developmental toxicity of TMBPA using zebrafish (Danio rerio) as a model, exposing embryos to 0.5, 5, 50, and 200 μg/L TMBPA for 120 h. The results showed that treatment with 5, 50, and 200 μg/L TMBPA decreased the hatching rate of zebrafish embryos at 48 h post-fertilization (hpf), while no significant difference was observed at 72 hpf. Meanwhile, TMBPA exposure at all concentrations showed no significant effect on the survival rate. Furthermore, a high concentration of TMBPA (200 μg/L) significantly reduced the total length and suppressed swimming ability in zebrafish larvae. In addition, gene expression analysis revealed impacts on antioxidant system (cat, gpx, mn-sod, keap1, ucp2, nrf2), hypothalamic–pituitary–thyroid (HPT) axis (ttr, ugt1ab, trβ), cardiac developmental (tbx2b, myl7, bmp4, notch1b, amhc), and the hypothalamic–pituitary–adrenal (HPA) axis (pomca and nr3c1). The results indicated that TMBPA exposure adversely disrupted embryo hatching and larval development of zebrafish, accompanied by altering the expression of functional genes in larvae. These results provide further evidence for the potential environmental hazard posed by TMBPA. Full article