Warfarin-exposed zebrafish embryos resembles human warfarin embryopathy in a dose and developmental-time dependent manner - From molecular mechanisms to environmental concerns

Keratinocytes drive the epithelial hyperplasia key to sea lice resistance in coho salmon

BACKGROUND

Salmonid species have followed markedly divergent evolutionary trajectories in their interactions with sea lice. While sea lice parasitism poses significant economic, environmental, and animal welfare challenges for Atlantic salmon (Salmo salar) aquaculture, coho salmon (Oncorhynchus kisutch) exhibit near-complete resistance to sea lice, achieved through a potent epithelial hyperplasia response leading to rapid louse detachment. The molecular mechanisms underlying these divergent responses to sea lice are unknown.

RESULTS

We characterized the cellular and molecular responses of Atlantic salmon and coho salmon to sea lice using single-nuclei RNA sequencing. Juvenile fish were exposed to copepodid sea lice (Lepeophtheirus salmonis), and lice-attached pelvic fin and skin samples were collected 12 h, 24 h, 36 h, 48 h, and 60 h after exposure, along with control samples. Comparative analysis of control and treatment samples revealed an immune and wound-healing response that was common to both species, but attenuated in Atlantic salmon, potentially reflecting greater sea louse immunomodulation. Our results revealed unique but complementary roles of three layers of keratinocytes in the epithelial hyperplasia response leading to rapid sea lice rejection in coho salmon. Our results suggest that basal keratinocytes direct the expansion and mobility of intermediate and, especially, superficial keratinocytes, which eventually encapsulate the parasite.

CONCLUSIONS

Our results highlight the key role of keratinocytes in coho salmon's sea lice resistance and the diverged biological response of the two salmonid host species when interacting with this parasite. This study has identified key pathways and candidate genes that could be manipulated using various biotechnological solutions to improve Atlantic salmon sea lice resistance.

Pregnancy outcomes in Chinese women with mechanical heart valves receiving warfarin treatment throughout pregnancy: 14-year experience

OBJECTIVE

The purpose was to evaluate pregnancy outcomes and risk factors associated with fetal complications in Chinese pregnant women with mechanical heart valves (MHVs) taking low-dose warfarin, aiming to fill in the research gap of this area.

METHODS

Between June 2010 and Aug 2023, 122 patients with MHVs who had 151 pregnancies and received warfarin throughout pregnancy were included. We compared them with 302 paired pregnancies without warfarin treatment. Binary logistic regression analyses were performed to explore risk predictors of fetal complications.

RESULTS

Pregnancy loss rate was 37.1 % in women taking warfarin, compared to only 4.6 % for those without warfarin exposure in pregnancy (RR = 8.00, 95 % CI: 4.61-13.90). In pregnant women with MHVs, there were 34 spontaneous abortions, 22 stillbirths and 1 neonatal malformation. In the first, second and third pregnant trimesters of women with MHVs, fetal complication incidences were 19.2 %, 9.9 % and 8.0 %, respectively. 86.0 % of fetal complications occurred in women taking a warfarin dose ≤5 mg/d, accounting for 94.0 % of the total population. The newborns' birth weight, gestational age and 1-minute Apgar score were significantly lower in pregnancies treated with warfarin compared to those without warfarin exposure. Only 2.0 % of postpartum hemorrhage and no thrombosis or maternal mortality data were collected in pregnant women on warfarin in this study.

CONCLUSION

Most Chinese pregnant women take a warfarin daily dose ≤5 mg and they might have only around 60 % chance of giving birth to a live baby without maternal complications.

Toxicology of chemical biocides: Anticoagulant rodenticides - Beyond hemostasis disturbance

The use of anticoagulant rodenticides (ARs) is one of the most commonly employed management methods for pest rodents. ARs compete with vitamin K (VK) required for the synthesis of blood clotting factors in the liver, resulting in inhibition of blood coagulation and often animal death due to hemorrhage. Besides rodents (target species), ARs may affect non-target animal species and humans. Out of hemostasis disturbance, the effects of ARs may be related to the inhibition of proteins that require VK for their synthesis but are not involved in the coagulation process, to their direct cytotoxicity, and their pro-oxidant/proinflammatory activity. A survey of the cellular and molecular mechanisms of these sublethal/asymptomatic AR effects is given in this review. Data from field, clinical, and experimental studies are presented. Knowledge of these mechanisms might improve hazard characterization and identification of potential ecotoxicological risks associated with ARs, contributing to a safer use of these chemicals.

Zebrafish Models to Study Ectopic Calcification and Calcium-Associated Pathologies

Ectopic calcification refers to the pathological accumulation of calcium ions in soft tissues and is often the result of a dysregulated action or disrupted function of proteins involved in extracellular matrix mineralization. While the mouse has traditionally been the go-to model organism for the study of pathologies associated with abnormal calcium deposition, many mouse mutants often have exacerbated phenotypes and die prematurely, limiting the understanding of the disease and the development of effective therapies. Since the mechanisms underlying ectopic calcification share some analogy with those of bone formation, the zebrafish (Danio rerio)-a well-established model for studying osteogenesis and mineralogenesis-has recently gained momentum as a model to study ectopic calcification disorders. In this review, we outline the mechanisms of ectopic mineralization in zebrafish, provide insights into zebrafish mutants that share phenotypic similarities with human pathological mineralization disorders, list the compounds capable of rescuing mutant phenotypes, and describe current methods to induce and characterize ectopic calcification in zebrafish.

Fish Microbiome Modulation and Convenient Storage of Aquafeeds When Supplemented with Vitamin K1

Vitamin K (VK) is a fat-soluble vitamin necessary for fish metabolism and health. VK stability as dietary component during aquafeed storage and its potential effect on intestinal microbiome in fish have not yet been completely elucidated. The convenient storage conditions of aquafeeds when supplemented with phylloquinone (VK1), as well as its potential effects on the gut microbiota of Senegalese sole (Solea senegalensis) juveniles, have been explored. Experimental feeds were formulated to contain 0, 250 and 1250 mg kg^-1 of VK1 and were stored at different temperatures (4, -20 or -80 °C). VK stability was superior at -20 °C for short-term (7 days) storage, while storing at -80 °C was best suited for long-term storage (up to 3 months). A comparison of bacterial communities from Senegalese sole fed diets containing 0 or 1250 mg kg^-1 of VK1 showed that VK1 supplementation decreased the abundance of the Vibrio, Pseudoalteromonas, and Rhodobacterace families. All these microorganisms were previously associated with poor health status in aquatic organisms. These results contribute not only to a greater understanding of the physiological effects of vitamin K, particularly through fish intestinal microbiome, but also establish practical guidelines in the industry for proper aquafeed storage when supplemented with VK1.

Short-term exposure to pharmaceuticals negatively impacts marine flatfish species: Histological, biochemical and molecular clues for an integrated ecosystem risk assessment

The marine habitat and its biodiversity can be impacted by released pharmaceuticals. The short-term (7 days) effect of 3 commonly used drugs - warfarin, dexamethasone and imidazole - on Senegalese sole (Solea senegalensis) juveniles was investigated. Occurrence of hemorrhages, histopathological alterations, antioxidant status, activity of antioxidant enzymes and expression of genes involved in the xenobiotic response (pxr, abcb1 and cyp1a), were evaluated. The results showed a time and drug-dependent effect. Warfarin exposure induced hemorrhages, hepatocyte vacuolar degeneration, and altered the activity of glutathione peroxidase (GPx) and the expression of all the studied genes. Dexamethasone exposure increased liver glycogen content, altered antioxidant status, GPx and superoxide dismutase activities, as well as abcb1 and cyp1a expression. Imidazole induced hepatocyte vacuolar degeneration and ballooning, and altered the antioxidant status and expression of the tested genes. The present work anticipates a deeper impact of pharmaceuticals on the aquatic environment than previously reported, thus underlining the urgent need for an integrated risk assessment.

Early detection of cyanide, organophosphate and rodenticide pollution based on locomotor activity of zebrafish larvae

Cyanide, organophosphate and rodenticides are highly toxic substances widely used in agriculture and industry. These toxicants are neuro- and organotoxic to mammals at low concentrations, thus early detection of these chemicals in the aqueous environment is of utmost importance. Here, we employed the behavioral toxicity test with wildtype zebrafish larvae to determine sublethal concentrations of the above mentioned common environmental pollutants. After optimizing the test with cyanide, nine rodenticides and an organophosphate were successfully tested. The compounds dose-dependently initially (0-60-min exposure) stimulated locomotor activity of larvae but induced toxicity and reduced swimming during 60-120-min exposure. IC₅₀ values calculated based on swimming distance after 2-h exposure, were between 0.1 and 10 mg/L for both first-generation and second-generation anticoagulant rodenticides. Three behavioral characteristics, including total distance travelled, sinuosity and burst count, were quantitatively analyzed and compared by hierarchical clustering of the effects measured by each three parameters. The toxicity results for all three behavioral endpoints were consistent, suggesting that the directly measured parameter of cumulative swimming distance could be used as a promising biomarker for the aquatic contamination. The optimized method herein showed the potential for utilization as part of a monitoring system and an ideal tool for the risk assessment of drinking water in the military and public safety.

In Silico Analysis to Identify Molecular Targets for Chemicals of Concern: The Case Study of Flocoumafen, an Anticoagulant Pesticide

Rodenticides are pesticides used worldwide, with little information available regarding health consequences in wildlife and humans. The aim of the present study was to use virtual screening to identify potential targets for flocoumafen, a superwarfarin rodenticide. Blind docking of more than 841 human proteins was carried out employing AutoDock Vina. The strength of the ligand interaction with the proteins was quantified based on the binding affinity score (kcal/mol). Results indicate that flocoumafen could be a promiscuous ligand for diversity of cellular protein targets. The best complexes were obtained for prostaglandin F synthase (-14.2 kcal/mol) and serum albumin (-14.0 kcal/mol) followed by glucocorticoid receptor 2, matrix metalloproteinase-9, nuclear receptor ROR-alpha, and activin receptor type-1, all with values equal or better than -13.5 kcal/mol. Docking method validation based on the root-mean-square deviation showed that flocoumafen had good capability to predict corresponding co-crystallized poses; and molecular dynamics simulations suggested the complex with greater binding affinity was thermodynamically stable. Protein-protein interaction networks built with main protein targets revealed that protein kinase B (AKT1), ribosomal protein S6 kinase B1 (RPS6KB1), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), retinoid X receptor alpha (RXRA), and protein phosphatase 2 catalytic subunit alpha (PPP2CA) were major hub proteins, whereas the gene ontology analysis reported that cellular response to endogenous stimulus, protein binding, and the TOR complex were the biological processes, molecular function, and cell component enrichments, respectively. These results should motivate more ecotoxicity testing for flocoumafen and other superwarfarins, as well as precautionary legislation to minimize exposure to these highly toxic chemicals. Environ Toxicol Chem 2021;40:2034-2043. © 2021 SETAC.

Biochemical and molecular responses of the Mediterranean mussel (Mytilus galloprovincialis) to short-term exposure to three commonly prescribed drugs

Pharmaceuticals represent a group of emerging contaminants. The short-term effect (3 and 7 days) of warfarin (1 and 10 mg L^-1), dexamethasone (0.392 and 3.92 mg L^-1) and imidazole (0.013 and 0.13 mg L^-1) exposure was evaluated on mussels (Mytilus galloprovincialis). Total antioxidant status, glutathione reductase, glutathione peroxidase (GPx) and superoxide dismutase enzyme activities, and the expression of genes involved in the xenobiotic response (ATP binding cassette subfamily B member 1 (abcb1) and several nuclear receptor family J (nr1j) isoforms), were evaluated. All nr1j isoforms are suggested to be the xenobiotic receptor orthologs of the NR1I family. All drugs increased GPx activity and altered the expression of particular nr1j isoforms. Dexamethasone exposure also decreased abcb1 expression. These findings raised some concerns regarding the release of these pharmaceuticals into the aquatic environment. Thus, further studies might be needed to perform an accurate environmental risk assessment of these 3 poorly studied drugs.

Role of emerging vitamin K‑dependent proteins: Growth arrest‑specific protein 6, Gla‑rich protein and periostin (Review)

Vitamin K‑dependent proteins (VKDPs) are a group of proteins that need vitamin K to conduct carboxylation. Thus far, scholars have identified a total of 17 VKDPs in the human body. In this review, we summarize three important emerging VKDPs: Growth arrest‑specific protein 6 (Gas 6), Gla‑rich protein (GRP) and periostin in terms of their functions in physiological and pathological conditions. As examples, carboxylated Gas 6 and GRP effectively protect blood vessels from calcification, Gas 6 protects from acute kidney injury and is involved in chronic kidney disease, GRP contributes to bone homeostasis and delays the progression of osteoarthritis, and periostin is involved in all phases of fracture healing and assists myocardial regeneration in the early stages of myocardial infarction. However, periostin participates in the progression of cardiac fibrosis, idiopathic pulmonary fibrosis and airway remodeling of asthma. In addition, we discuss the relationship between vitamin K, VKDPs and cancer, and particularly the carboxylation state of VKDPs in cancer.

Dysregulation of lipid metabolism in PLHC-1 and ZFL cells exposed to tributyltin an all-trans retinoic acid

There is increasing awareness that exposure to endocrine disrupters interferes with lipid homeostasis in vertebrates, including fish. Many of these compounds exert their action by binding to nuclear receptors, such as peroxisome proliferator-activated receptors and retinoid X receptor. This work investigates the use of fish liver cells (PLHC-1 and ZFL cells) for the screening of metabolic and lipid disrupters in the aquatic environment by assessing changes in the cell's lipidome after exposure to the model compounds, tributyltin chloride and all-trans retinoic acid. Lipid extracts, analyzed by FIA-ESI (+/-) Orbitrap, evidenced the intracellular accumulation of triglycerides and diglycerides in both cell models after exposure to 100 and 200 nM tributyltin chloride for 24 h. Exposure to 1 μM all-trans retinoic acid led to a significant accumulation of triglycerides in PLHC-1 cells, while few triglycerides were accumulated in ZFL cells. Retinoic acid (cyp26b1, cyp3a65, lrata) and lipid metabolism (fasn, scd, elovl6) related genes were up-regulated by tributyltin chloride and all-trans retinoic acid, while only all-trans retinoic acid down-regulated the expression of dgat1a. The two cell models show sensitivity and responses to tributyltin chloride and all-trans retinoic acid comparable to those previously reported in mammalian cells. These results support the use of fish liver cells as alternative models for the detection of contaminants that act as lipid disrupters in the aquatic environment.

Vitamin K in Vertebrates' Reproduction: Further Puzzling Pieces of Evidence from Teleost Fish Species

Vitamin K (VK) is a fat-soluble vitamin that vertebrates have to acquire from the diet, since they are not able to de novo synthesize it. VK has been historically known to be required for the control of blood coagulation, and more recently, bone development and homeostasis. Our understanding of the VK metabolism and the VK-related molecular pathways has been also increased, and the two main VK-related pathways-the pregnane X receptor (PXR) transactivation and the co-factor role on the γ-glutamyl carboxylation of the VK dependent proteins-have been thoroughly investigated during the last decades. Although several studies evidenced how VK may have a broader VK biological function than previously thought, including the reproduction, little is known about the specific molecular pathways. In vertebrates, sex differentiation and gametogenesis are tightly regulated processes through a highly complex molecular, cellular and tissue crosstalk. Here, VK metabolism and related pathways, as well as how gametogenesis might be impacted by VK nutritional status, will be reviewed. Critical knowledge gaps and future perspectives on how the different VK-related pathways come into play on vertebrate's reproduction will be identified and proposed. The present review will pave the research progress to warrant a successful reproductive status through VK nutritional interventions as well as towards the establishment of reliable biomarkers for determining proper nutritional VK status in vertebrates.

New Insights on Vitamin K Metabolism in Senegalese sole (Solea senegalensis) Based on Ontogenetic and Tissue-Specific Vitamin K Epoxide Reductase Molecular Data

Vitamin K (VK) is a key nutrient for several biological processes (e.g., blood clotting and bone metabolism). To fulfill VK nutritional requirements, VK action as an activator of pregnane X receptor (Pxr) signaling pathway, and as a co-factor of γ-glutamyl carboxylase enzyme, should be considered. In this regard, VK recycling through vitamin K epoxide reductases (Vkors) is essential and should be better understood. Here, the expression patterns of vitamin K epoxide reductase complex subunit 1 (vkorc1) and vkorc1 like 1 (vkorc1l1) were determined during the larval ontogeny of Senegalese sole (Solea senegalensis), and in early juveniles cultured under different physiological conditions. Full-length transcripts for ssvkorc1 and ssvkorc1l1 were determined and peptide sequences were found to be evolutionarily conserved. During larval development, expression of ssvkorc1 showed a slight increase during absence or low feed intake. Expression of ssvkorc1l1 continuously decreased until 24 h post-fertilization, and remained constant afterwards. Both ssvkors were ubiquitously expressed in adult tissues, and highest expression was found in liver for ssvkorc1, and ovary and brain for ssvkorc1l1. Expression of ssvkorc1 and ssvkorc1l1 was differentially regulated under physiological conditions related to fasting and re-feeding, but also under VK dietary supplementation and induced deficiency. The present work provides new and basic molecular clues evidencing how VK metabolism in marine fish is sensitive to nutritional and environmental conditions.

Acute toxicity and clotting times of anticoagulant rodenticides to red-toothed (Odonus niger) and black (Melichthys niger) triggerfish, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides)

Anticoagulant rodenticides (ARs) are used in rat eradication efforts on island wildlife refuges. AR bait pellets can get into coral reef areas during broadcasting and lead to exposure of non-target organisms, such as marine fishes. The objective of this study was to determine the sensitivity of representative saltwater fishes, Red-toothed triggerfish (Odonus niger) and Black triggerfish (Melichthys niger), and common freshwater fishes, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides) to first generation ARs, diphacinone (DPN) and chlorophacinone (CPN), as well as a second-generation AR, brodifacoum (BROD). Acute toxicity of ARs was evaluated by single dose, intraperitoneal injections. The median lethal dose (LD50) ranges were 137-175 μg DPN/g, 155-182 μg CPN/g, and 36-48 μg BROD/g for Red-toothed triggerfish and 90-122 μg DPN/g, 125-164 μg CPN/g, and 50-75 μg BROD/g for black triggerfish. Laboratory surrogate test fish species fathead minnow and largemouth bass were of similar sensitivity toward AR-induced toxicity compared to triggerfish based on LD50 values. Sublethal effects on elevated clotting time occurred in dose-dependent fashion in all fish tested. Fish appear to have low sensitivity to AR chemicals as compared to other taxa, in particular mammals and birds, based on across-taxa comparisons of species sensitivity distributions of whole body, single dose acute lethality (LD50 values). The sensitivity of fish to waterborne exposures of ARs has yet to be fully evaluated and indeed may prove more hazardous to fish.