Engineering heart-like organoids in vitro holds significant promise for advancing cardiovascular research. While current approaches, such as suspended cell clusters in media or encapsulating them in gels, have shown potential, they are often challenged in generating organoids with defined chambers and synchronized contractions due to variations in outcomes linked to cell density. In this study, we present a strategy to modulate cell-cell interactions at a fixed cell density by mimicking bioprocesses underlying embryo implantation and invasion. Specifically, an embryoid body cultured on a collagen-poly(ethylene glycol) gel with greater porosity and hydrophilicity and lower stiffness than a pure collagen gel undergoes enhanced invasion and self-organization, resulting in functional, embryo-like cardiac organoids. These organoids exhibit distinct chamber structures surrounded by cardiac muscle, pacemaker cell innervation, atrioventricular synchrony-like contractions, recurring calcium flux, and electrocardiogram-like signals. Organoid development is associated with upregulated expression of mesodermal, ectodermal, and N-cadherin genes. This simple yet effective approach will enable robust modeling of heart physiology and drug response in vitro, offering valuable insights for translational cardiovascular research.

Microplastic pollution has emerged as a global issue that poses serious risks to aquatic ecosystems. Although Daphnia spp. are widely used as model organisms to study the effects of microplastics on their fitness, their microbiome response remains largely unexplored. This study investigated the effects of ground polystyrene microplastics (G-PS; fragments below the EC10 value) and commercial polystyrene microplastics (C-PS; beads below the EC10 value) on the physio-biochemical responses and gut microbiota of Daphnia magna. The toxicity of polystyrene microplastics to D. magna was shape-dependent, with G-PS being more toxic than C-PS. Exposure to G-PS and C-PS triggered Reactive oxygen species (ROS) production in D. magna. Although G-PS increased the abundance of both harmful (Fusobacterium) and beneficial bacteria (Blautia and Subdoligranulum) in the gut microbiota of Daphnia, C-PS only increased the abundance of beneficial bacteria (Lactobacillus, Ligilactobacillus, and Aerococcus), which may mitigate the toxicity of microplastics. Functional predictions based on amplicon sequencing suggested that altered microbiota may support the growth of D. magna by modulating associated metabolic pathways. D. magna exposed to G-PS exhibited a significantly higher abundance of gut microbiota pathways and enzymes associated with the detoxification of harmful compounds than those exposed to C-PS. This suggests that the higher toxicity of G-PS requires a stronger adaptive response from the gut microbiota. Overall, these findings highlight microplastic shape as a key factor influencing toxicity in D. magna and its associated microbiota.

The androgen receptor (AR) activation by androgens is vital for tissue development, sexual differentiation, and reproductive attributes in zebrafish (Danio rerio). However, our understanding of the molecular mechanisms behind their activation remains limited. In this study, we employed both ab initio (AlphaFold) and homology (SWISS-MODEL) structure models of zebrafish androgen receptor ligand-binding domain (zAR-LBD) to explore the binding specificity, binding affinity, and molecular interactions of endogenous hormones (testosterone (T), 11-ketotestosterone (11-KT), and dihydrotestosterone (DHT)) in a computational simulation. Molecular docking analysis showed that both structures formed the same interactions and similar patterns of binding energy with androgens. Molecular Dynamics (MD) simulation analysis revealed that hydrogen bond occupancy aligned with in vitro findings related to androgenic effect. When comparing complexes modeled by SWISS-MODEL and AlphaFold, significant differences were observed in root mean square deviation (RMSD) and root mean square fluctuations (RMSF). The AlphaFold structures also exhibited a clear separation between ligands in principal component analysis. Further correlation analysis between in silico features and in vitro EC50 values identified MMPBSA energies as the most significant contributors to ligand-specific variance in the in silico complexes (p < 0.05). Overall, this integrative approach offers significant insights into the molecular mechanisms underlying zebrafish AR activity.

Medical stents are vital for treating vascular complications and restoring blood flow in millions of patients. Despite its widespread effectiveness, restenosis, driven by the complex interplay of cellular responses, remains a concern. This study investigated the reactions of vascular cells to nano/microscale wrinkle (nano-W and micro-W) patterns created on laser-textured nitinol (NiTi) surfaces by adjusting laser processing parameters, such as spot overlap ratio and line overlap ratio. Evaluation of topographical effects on endothelial and smooth muscle cells (SMCs) revealed diverse morphologies, proliferation rates, and gene expressions. Notably, microscale wrinkle patterns exhibited reduced monocyte adhesion and inflammation-related gene expression, demonstrating their potential applications in mitigating vascular complications after stent insertion. Additionally, an ex vivo metatarsal assay was utilized to bridge the gap between in vitro and in vivo studies, demonstrating enhanced angiogenesis on laser-textured NiTi surfaces. Laser-textured NiTi exhibits a guided formation process, emphasizing their potential to promote swift endothelialization. These findings underscore the efficacy of laser texturing for tailored cellular interactions on metallic surfaces and offer valuable insights into optimizing biocompatibility and controlling cellular responses, which may pave the way for innovative advances in vascular care and contribute to the ongoing improvement of stent insertion.

Diving birds, particularly those sharing coastal habitats with fishing grounds, are at risk from oil pollution. Despite documented cases of bird mortality, the specific role of oil pollution in these death remains unclear. To address this knowledge gap, this study examined polycyclic aromatic hydrocarbon (PAH) contamination, its sources, and its impact on loon health. An analysis of 86 carcasses from three species of loons revealed drowning as the leading cause of death, followed by oil pollution and unknown debilitation. While liver concentrations of 16 PAHs (& sum;PAHs) showed no significant variation by sex, location, species, or cause of death, it was evident that wintering loons were exposed to PAH pollution along South Korea's eastern coast. The ratio of low (di- and tricyclic) to high (tetra-, penta-, and hexa-cyclic) molecular weight PAHs was approximately 3-5 across all three loon species. From 2010 to 2017, the composition of PAHs shifted, with a decline in low molecular weight PAHs (indicative of petrogenic sources) and a concerning increase in high molecular weight PAHs (associated with pyrogenic sources). This trend coincided with a tenfold increase in the toxic equivalency quotient of benzo[a] pyrene (TEQ(BaP)), despite a decrease in overall & sum;PAH concentrations. The detection of benzo[a]pyrene diol epoxide (BPDE)-DNA adducts in some loons further suggests potential genotoxic effects from PAH exposure. These findings underscore the persistent PAH contamination affecting wintering loons. Continued research is crucial to understand the evolving threats posed by PAHs and to support the conservation of these migratory birds along the North America-Asia flyway.

This study investigates polystyrene (PS) microplastics impact on the freshwater crustacean Daphnia magna, a sentinel species for environmental monitoring. Rather than utilizing their commercial microplastic counterparts, realistic microplastic morphologies that mimic those found in natural aquatic ecosystems were used to assess the hazard PS particles pose to aquatic organisms. A comprehensive suite of biological endpoints, including immobilization rates, generation of reactive oxygen species (ROS), expression levels of ROS-related genes and wide-ranging transcriptomic profiling, was encompassed in our methodology. This study, through these multifaceted experimental approaches, aimed to elucidate the detrimental effects of PS exposure on the early life stages of D. magna, i.e., neonates, with an emphasis on oxidative stress. The EC10 (effective concentration for 10% of the population) of ground PS (G-PS, fragments) was lower than that of purchased PS (C-PS, beads) in the immobilization test, resulting in the complete daphnid mortality. To advance the mechanistic understanding of microplastic-induced stress responses, a key goal was to integrate transcriptomic data with gene expression patterns. Daphnids exposed to PS fragments increased their oxidative stress response genes. However, in those exposed to PS beads, oxidative stress-related genes were not found in the top-10 expression of cellular components from the transcriptome. By illuminating the molecular responses induced by different shapes of microplastics in D. magna, the results of this research significantly expand the knowledge of microplastic impacts on aquatic ecosystem. We aim to provide insights into the ecological risks associated with microplastic pollution by understanding how varying shapes of microplastics affect this keystone species.

Stem cell-derived neuron-glia models provide a robust platform for studying brain physiology, developing therapeutics, and exploring biocomputation. Extracellular vesicles (EVs) containing neurotrophic factors, also derived from stem cells, have the capacity to facilitate the formation of neural networks within these systems. However, their bioactivity is often compromised by the propagation of oxidative stress between cells during their manufacture, limiting reproducibility. Here, the Cellular Redox Spreading Shield (CROSS) is introduced as a droplet microfluidic-assembled antioxidant crystal-loaded microgel that sustains antioxidant activity for up to 6-7 days in stem cell cultures. In mesenchymal stromal cell (MSC) cultures, CROSS mitigates oxidation propagation and preserves potent neurotrophic EV production. These EVs, specifically enriched with neurotrophic microRNAs, enhance neural stem cell differentiation into neuron-glia networks, characterized by increased synaptic density and functional connectivity, as determined by calcium transient imaging combined with graph theory. In contrast, EVs from untreated, oxidatively stressed MSCs impair neural stem cell differentiation and network formation. This work highlights the importance of CROSS in stabilizing cellular production of neurotrophic EVs, with broad implications for neural tissue regeneration and biohybrid technologies.

Cigarette filters are the most common form of litter worldwide and pose significant ecological risks because they degrade into microfibers and microplastics in aquatic environments. While previous studies have focused on the acute toxicity of cigarette leachate, the long-term ecological consequences of microplastic release from cigarette filters remain largely unexplored. This study evaluated the toxicity of cigarette filter-derived microplastics, including non-smoked cellulose acetate filters (CAF), smoked cigarette filters (GSF), on Daphnia magna, as well as leachate from smoked filter (LSF) for comparison. Imaging analysis confirmed that D. magna ingested cigarette filter-derived microplastics, which acted as carriers, gradually releasing harmful substances within organisms, a phenomenon consistent with the Trojan horse effect. Acute toxicity tests revealed similar 48-hour EC50 values (∼50 mg/L) for both GSF and LSF; however, GSF induced more pronounced long-term toxic effects. Chronic exposure to GSF significantly impairs reproduction, delays the timing of the first brood, reduces offspring size, and disrupts ecdysteroid-regulated genes. These findings indicate that cigarette filters are a persistent source of chemical pollution, threatening aquatic ecosystems. Specifically, microplastics from discarded cigarette filters act as Trojan horses, continuously releasing toxic chemicals and transporting hydrophobic contaminants, amplifying their environmental impact.

Polystyrene is widely used in disposable products and is now a ubiquitous plastic pollutant in aquatic environments, where it degrades into smaller particles that leach potentially toxic chemicals. However, knowledge regarding the impacts of plastic leachates remains limited. This study investigates the lethal and nonlethal effects of polystyrene leachate on two ecologically significant aquatic organisms, Daphnia magna (water flea) and Artemia salina (brine shrimp). Polystyrene leachates were prepared in seawater, freshwater, and sterile, pure water by incubating the material in each of the media under natural conditions for six months. D. magna and A. salina were exposed to varying concentrations of the leachates under controlled laboratory conditions, monitoring their survival, as well as measuring reactive oxygen species and antioxidant responses as superoxide dismutase and catalase activity. The data show that A. salina was more significantly affected with higher mortality observed at lower leachate concentrations, potentially linked to seawater enhancing the leaching of toxic additives. Moreover, at non-lethal concentrations, the antioxidative responses maintained homeostasis in both organisms. Considering the current reported microplastic concentrations in the aquatics and the adequate antioxidative response, leachate from plastic potentially does not pose a severe threat to these organisms. Nevertheless, hydrological characteristics of waterbodies may cause microplastic hotspots, which could significantly concentrate plastics and thus their leachates, necessitating action to reduce the current microplastic pollution level and avoid future surges. This study highlights the ecological significance of polystyrene pollution, emphasizing the need for more comprehensive regulatory measures and the development of sustainable alternatives to polystyrene-based products. The distinct responses of D. magna and A. salina imply that the impact of plastic pollution varies among species, necessitating further research to elucidate broader ecological consequences. Understanding how polystyrene leachate affects keystone species provides crucial insights into the overall implications for aquatic ecosystems.

The main MoR discussion led to further suggestions on KE terminology, including ensuring coherence to directionality in terms of the KE descriptions (e.g., specifying increase, decrease, altered, no direction, etc.) and clarifying differences in ROS and reactive oxygen and nitrogen species (RONS), and enzymatic and non-enzymatic events.The consortium highlighted the importance of the role of ROS as a KE and an associative event in the AOP framework.Additionally, participants highlighted modification to macromolecules from the resultant RONS generation (e.g., lipid peroxidation) as a relevant endpoint to include in the KE.The possibility of grouping ROS-related KEs in the AOP framework needs to be discussed further.

•Active sites of δ-MnO2 to degrade BPA were maximized by loading on porous materials.•BPA was degraded by 99% within 20 min with δ-MnO2 composite materials.•δ-MnO2-PDA-diatoms can be recycled with sustained BPA removal ∼ 99%.•The residues degraded from BPA do not have harmful effects with in vitro study.•High capacity of BPA treatment process was achieved with δ-MnO2 packed column.

Bisphenol A (BPA), a building block of various plastics, is invading biosystems through drinking water and raising concerns about their adverse impacts on human health. Filtration, biological, and oxidation methods have been developed to decontaminate BPA, but high energy demand or lengthy biodegradation process acts as limiting factors. Recently, 8-MnO2 with layered structure has emerged as a promising tool for BPA degradation. However, the reaction rate of BPA degradation suffers from the nature of aggregation in free-standing 8-MnO2 nanosheets with limited accessible active sites towards BPA. To overcome this critical challenge, this study demonstrates that the immobilization of 8-MnO2 nanosheets on a porous support can enhance BPA degradation rate due to the increased exposure of active sites of 8-MnO2. As a result, the 8-MnO2 nanosheets immobilized on porous diatom particles via polydopamine (PDA) binder degrades BPA (k' -0.774 L g-1 min-1) 14 times faster than free-standing 8-MnO2 (k' -0.056 L g- 1 min-1). Furthermore, the resulting 8-MnO2-PDA-diatom degrades 99 % of BPA within 20 min and can be recycled without any performance loss up to 7 times, providing the reusability towards BPA removal in a sustainable and eco-friendly manner. More importantly, the degraded products of BPA resulting from radical transfers, coupling, and fragmentation reactions do not cause any estrogenic response or toxicity to ecological systems, as examined with human and fish cells. Finally, a column packed with 8-MnO2-PDA-diatom demonstrates 99 % BPA removal with continuous flows of BPA-spiked wastewater. We propose that this advanced system will be readily extended to remove a broad array of water contaminants that will disrupt the physiological function of organs and their roles in the endocrine cross-talk between the reproductive hormones.

Nanomaterials are widely believed to induce toxic effects on organisms by evoking oxidative stress. We evaluated the toxic effects of nanomaterials on the cardiac and behavioral changes in Daphnia magna under varying exposure conditions. Titanium dioxide nanoparticles (TiO2 NPs), silver nanoparticles (AgNPs), and silver nitrate (AgNO3) were selected for the acute toxicity tests. The adverse effects of the substances on the neonates including heart rate, swimming speed, and oxidative stress were measured. The heart rate level decreased as the concentration of both NPs and silver ions (Ag+) increased. The average swimming speed was measured to be approximately 15 mm/min for the control group. The swimming speed generally increased with a longer exposure to both NPs although it reached a plateau at the lowest concentration of AgNPs. A similar but less clear trend was observed for Ag+. For all substances, the overall swimming speed exhibited no correlation or weak negative correlations with the exposure concentration. The oxidative stress levels increased after exposure compared with the control group. We conclude that aquatic nanotoxicity tests should consider multilevel physicochemical, physiological, and behavioral parameters for the official guidelines to quantify more robust adverse outcomes.

sient ROS play an important role in the defense mechanism of immune cells and redox signaling, whereas prolonged ROS elevation is involved in disease development and progression.With global progress in the AOP development field, multiple, slightly nuanced KEs related to ROS have been created in the AOP-Wiki 2 .Many of these KEs are highly similar and largely redundant, which has catalyzed a need to create harmonized consensus KEs on ROS that can be shared in a modular fashion between closely related pathways and networks.To address this need, a consortium of ROS and AOP experts has been formed to discuss the "Mystery of ROS" and develop consensus KEs for this field.This meeting report summarizes initial efforts of the "Mystery of ROS" consortium to harmonize the ROS-related KEs currently available in the AOP-Wiki.The two new modular KEs reflect discussion from the group relating to the effects of ROS presenting a "double-edged sword" by describing the concepts of "up-regulation of ROS" and "diminished protective response." Summary of the discussions in the consortiumThe international online conferences on the Mystery of ROS took place on May 31, 2021 and October 8, 2021.At the first conference on Mystery of ROS (I), a brief introduction of the ROS collaboration was followed by eight presentations, which are listed in Table 1.

Abstract Titanium dioxide, frequently used in commonplace products, is now regularly detected in aquatic environments. Understanding its toxic effects on native biota is essential; however, combined toxicity with commonly occurring pollutants, such as the pharmaceutical diclofenac, may provide more insight into environmental situations. Therefore, the present study aimed to evaluate the effects of titanium dioxide and diclofenac, individually and combined, on the macrophyte Egeria densa. DCF uptake and removal were assessed. DCF and titanium dioxide toxicity were evaluated by assaying enzymes as bioindicators of biotransformation and oxidative stress. Cytosolic glutathione S-transferase and glutathione reductase activities were increased by diclofenac, titanium dioxide, and the combination. Both enzymes’ activities were more significantly elevated by diclofenac and the combination than nanoparticles alone. Microsomal glutathione S-transferase was unaffected by diclofenac exposure but inhibited with titanium dioxide and the mixture. Diclofenac elicited the most significant response. Based on the macrophytes’ vitality, the cytosolic enzymes effectively prevented damage.

The environmental impacts of plastic pollution have recently attracted universal attention, especially in the aquatic environment. However, research has mostly been focused on marine ecosystems, even though freshwater ecosystems are equally if not more polluted by plastics. In addition, the mechanism and extent to which plastic pollution affects aquatic biota and the rates of transfer to organisms through food webs eventually reaching humans are poorly understood, especially considering leaching hazardous chemicals. Several studies have demonstrated extreme toxicity in freshwater organisms such Daphnia. When such keystone species are affected by ambient pollution, entire food webs are destabilized and biodiversity is threatened. The unremitting increase in plastic contaminants in freshwater environments would cause impairments in ecosystem functions and structure, leading to various kinds of negative ecological consequences. As various studies have reported the effects on daphnids, a consolidation of this literature is critical to discuss the limitations and knowledge gaps and to evaluate the risk posed to the aquatic environment. This review was undertaken due to the evident need to evaluate this threat. The aims were to provide a meaningful overview of the literature relevant to the potential impact of plastic pollution and associated contaminants on freshwater daphnids as primary consumers. A critical evaluation of research gaps and perspectives is conducted to provide a comprehensive risk assessment of microplastic as a hazard to aquatic environments. We outlined the challenges and limitations to microplastic research in hampering better-focused investigations that could support the development of new plastic materials and/or establishment of new regulations.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed as a result of natural cellular processes, intracellular signaling, or as adverse responses associated with diseases or exposure to oxidizing chemical and non-chemical stressors. The action of ROS and RNS, collectively referred to as reactive oxygen and nitrogen species (RONS), has recently become highly relevant in a number of adverse outcome pathways (AOPs) that capture, organize, evaluate and portray causal relationships pertinent to adversity or disease progression. RONS can potentially act as a key event (KE) in the cascade of responses leading to an adverse outcome (AO) within such AOPs, but are also known to modulate responses of events along the AOP continuum without being an AOP event itself. A substantial discussion has therefore been undertaken in a series of workshops named "Mystery or ROS" to elucidate the role of RONS in disease and adverse effects associated with exposure to stressors such as nanoparticles, chemical, and ionizing and non-ionizing radiation. This review introduces the background for RONS production, reflects on the direct and indirect effects of RONS, addresses the diversity of terminology used in different fields of research, and provides guidance for developing a harmonized approach for defining a common event terminology within the AOP developer community.