Neurotoxic effects of polystyrene nanoplastics on memory and microglial activation: Insights from in vivo and in vitro studies

Nanoplastics, arising from the fragmentation of plastics into environmental pollutants and specialized commercial applications, such as cosmetics, have elicited concerns due to their potential toxicity. Evidence suggests that the oral ingestion of nanoplastics smaller than 100 nm may penetrate the brain and induce neurotoxicity. However, comprehensive research in this area has been hampered by technical challenges associated with the detection and synthesis of nanoplastics. This study aimed to bridge this research gap by successfully synthesizing fluorescent polystyrene nanoplastics (PSNPs, 30-50 nm) through the incorporation of IR-813 and validating them using various analytical techniques. We administered PSNPs orally (10 and 20 mg/kg/day) to mice and observed that they reached brain tissues and induced cognitive dysfunction, as measured by spatial and fear memory tests, while locomotor and social behaviors remained unaffected. In vitro studies (200 μg/mL) demonstrated a predominant uptake of PSNPs by microglia over astrocytes or neurons, leading to microglial activation, as evidenced by immunostaining of cellular markers and morphological analysis. Transcriptomic analysis indicated that PSNPs altered gene expression in microglia, highlighting neuroinflammatory responses that may contribute to cognitive deficits. To further explore the neurotoxic effects of PSNPs mediated by microglial activation, we measured endogenous neuronal activity using a multi-electrode array in cultured hippocampal neurons. The application of conditioned media from microglia exposed to PSNPs suppressed neuronal activity, which was reversed by inhibitors of microglial activation. Our findings offer detailed insights into the mechanisms by which nanoplastics damage the brain, particularly emphasizing the potential environmental risk factors that contribute to cognitive impairment in neurodegenerative diseases.

Neurotoxicities induced by micro/nanoplastics: A review focusing on the risks of neurological diseases

Pollution of micro/nano-plastics (MPs/NPs) is ubiquitously prevalent in the environment, leading to an unavoidable exposure of the human body. Despite the protection of the blood-brain barrier, MPs/NPs can be transferred and accumulated in the brain, which subsequently exert negative effects on the brain. Nevertheless, the potential neurodevelopmental and/or neurodegenerative risks of MPs/NPs remain largely unexplored. In this review, we provide a systematic overview of recent studies related to the neurotoxicity of MPs/NPs. It covers the environmental hazards and human exposure pathways, translocation and distribution into the brain, the neurotoxic effects, and the possible mechanisms of environmental MPs/NPs. MPs/NPs are widely found in different environment matrices, including air, water, soil, and human food. Ambient MPs/NPs can enter the human body by ingestion, inhalation and dermal contact, then be transferred into the brain via the blood circulation and nerve pathways. When MPs/NPs are present in the brain, they can initiate a series of molecular or cellular reactions that may harm the blood-brain barrier, cause oxidative stress, trigger inflammatory responses, affect acetylcholinesterase activity, lead to mitochondrial dysfunction, and impair autophagy. This can result in abnormal protein folding, loss of neurons, disruptions in neurotransmitters, and unusual behaviours, ultimately contributing to the initiation and progression of neurodegenerative changes and neurodevelopmental abnormalities. Key challenges and further research directions are also proposed in this review as more studies are needed to focus on the potential neurotoxicity of MPs/NPs under realistic conditions.

Beyond disclaimers: The need for a curation-based model of PubMed

According to its own description, the biomedical meta-database PubMed exists "with the aim of improving health-both globally and personally." Unfortunately, PubMed contains an increasing amount of low-quality research that may detract from this goal. Currently, PubMed warns its users and protects itself from such problems with a disclaimer stating that the presence of any article, book, or document in PubMed does not imply an endorsement of, or concurrence with, its contents by the NLM, the National Institutes of Health (NIH), or the U.S. Federal Government. However, we are critical of a "disclaimer-only" stance and encourage PubMed to take further action against low-quality research being found and indexed in its database, and thus available for use. To address this problem, we offer two lines of reasoning to argue that PubMed should not function merely as a passive index of health-related research. Instead, we first argue that only trustworthy published research is able to further PubMed's goal of health improvement. Secondly, on the basis of surveys, we argue that researchers place a high level of trust in articles that are referenced in this meta-database. We cannot expect any one set of actors to ensure trustworthy content on PubMed, which requires collective responsibility among authors, peer reviewers, editors, and indexers alike. Instead, we propose a curation-based model that incorporates three mechanisms of collaborative content curation: open expert feedback on indexed content, journal auditing, and constant transparent reassessment of indexed entities.

Oral subacute polypropylene microplastics administration effect on potential immunotoxicity in ICR mice

Exposure to microplastics may be associated with damage of immune system. Polypropylene microplastics (PP-MPs) with a wide range of beneficial applications have not been extensively studied with respect to the immune system. The aim of this investigation is to examine the influence of two different sizes of PP-MPs (5.2 and 23.9 μm diameter) on immune system components in ICR mice. PP-MPs were administered orally to female and male mice at 0 (corn oil vehicle), 500, 1000, or 2000 mg/kg/d for single and daily for 4-week repeated toxicity test, respectively. No significant differences were observed in number of thymic CD4+, CD8+, CD4+CD8+ T lymphocytes, splenic helper T cells, cytotoxic T cells, and B cells. The ratio of interferon-γ to interleukin-4 in culture supernatants from activated splenocytes ex vivo (48 hr) was lower in females which were repeatedly administered with PP-MPs compared to vehicle irrespective of PP-MPs size and dose. In contrast, the opposite trend was observed in males. Production of tumor necrosis factor-α was upregulated in females that were repeatedly exposed to PP-MPs. The serum IgG2a/IgG1 ratio was lowered in female receiving large-size PP-MPs. Data suggest that immune disturbances resulting in predominant type-2 helper T cell reactivity may occur in mice, especially in females, when repeatedly exposed to PP-MPs. Further investigations with longer exposure periods are necessary to determine the immunotoxicities attributed to PP-MPs.

Physiological and transcriptomic responses of seawater halobios to micro/nano-scale polystyrene-cadmium exposure in a marine food web

Micro/nano-plastics (MPs/NPs) represent an emerging contaminant, posing a significant threat to oceanic halobios. While the adverse effects of joint pollutants on marine organisms are well-documented, the potential biological impacts on the food chain transmission resulting from combinations of MPs/NPs and heavy metals (HMs) remain largely unexplored. This study exposed the microbial loop to combined contaminants (MPs/NPs + HMs) for 48h, bacteria and contaminants are washed away before feeding to the traditional food chain, employing microscopic observation, biochemical detection, and transcriptome analysis to elucidate the toxicological mechanisms of the top predator. The findings revealed that MPs/NPs combined with Cd2+ could traverse both the microbial loop and classical food chain. Acute exposure significantly affected the carbon biomass of the top predator Tigriopus japonicus (75.8% lower). Elevated antioxidant enzyme activity led to lipid peroxidation, manifesting in increased malondialdehyde levels. Transcriptome sequencing showed substantial differential gene expression levels in T. japonicus under various treatments. The upregulation of genes associated with apoptosis and inflammatory responses, highlighting the impact of co-exposure on oxidative damage and necroptosis within cells. Notably, NPs-Cd exhibited stronger toxicity than MPs-Cd. NPs-Cd led to a greater decrease in the biomass of top predators, accompanied by lower activities of GSH, SOD, CAT, and GSH-PX, resulting in increased production of lipid peroxidation product MDA and higher oxidative stress levels. This investigation provides novel insights into the potential threats of MPs/NPs combined with Cd2+ on the microbial loop across traditional food chain, contributing to a more comprehensive assessment of the ecological risks associated with micro/nano-plastics and heavy metals.

Molecular insights into nanoplastics-peptides binding and their interactions with the lipid membrane

Micro- and nanoplastics have become a significant concern, due to their ubiquitous presence in the environment. These particles can be internalized by the human body through ingestion, inhalation, or dermal contact, and then they can interact with environmental or biological molecules, such as proteins, resulting in the formation of the protein corona. However, information on the role of protein corona in the human body is still missing. Coarse-grain models of the nanoplastics and pentapeptides were created and simulated at the microscale to study the role of protein corona. Additionally, a lipid bilayer coarse-grain model was reproduced to investigate the behavior of the coronated nanoplastics in proximity of a lipid bilayer. Hydrophobic and aromatic amino acids have a high tendency to create stable bonds with all nanoplastics. Moreover, polystyrene and polypropylene establish bonds with polar and charged amino acids. When the coronated nanoplastics are close to a lipid bilayer, different behaviors can be observed. Polyethylene creates a single polymeric chain, while polypropylene tends to break down into its single chains. Polystyrene can both separate into its individual chains and remain aggregated. The protein corona plays an important role when interacting with the nanoplastics and the lipid membrane. More studies are needed to validate the results and to enhance the complexity of the systems.

Liver Injury Induced by Exposure to Polystyrene Microplastics Alone or in Combination with Cadmium in Mice Is Mediated by Oxidative Stress and Apoptosis

Microplastics (MPs) have been considered an emerging environmental pollutant which, when combined with toxic metals, enter the circulatory system of mammals and eventually cause damage. Therefore, it is important to study the toxicity of the mixture of MPs and heavy metals for evaluating risk assessment of mammals. In the present study, the toxicological effects of different concentrations of polystyrene (PS)-MPs alone or in combination with cadmium chloride (CdCl2) during chronic exposure (8 weeks) were evaluated using intragastric administration in mice. Using comparative analysis, it was revealed that PS-MPs alone or in combination with Cd could destroy the normal structural morphology of liver tissue and increase the levels of two biochemical indicators of liver damage, thereby inducing changes in antioxidant and hyperoxide capacities. In addition, PS-MPs and/or Cd activated the antioxidant signaling pathway Nrf2-Keap1 and affected the endogenous apoptosis signaling pathway p53-Bcl-2/Bax, thus promoting apoptosis. These findings suggested that exposure to MPs alone or in combination with Cd led to adverse effects on the liver. Furthermore, it was revealed that co-exposure to MPs and Cd reduced Cd toxicity, thereby highlighting the possibility MPs may act as carriers of other toxic substances and coordinate with them. Therefore, evaluating the synergistic or anti-agonistic effects of MPs on the toxicity and bioavailability of xenobiotics is in the future critical in environmental toxicological studies.

A critical review on male-female reproductive and developmental toxicity induced by micro-plastics and nano-plastics through different signaling pathways

It is widely accepted that humans are constantly exposed to micro-plastics and nano-plastics through various routes, including inhalation of airborne particles, exposure to dust, and consumption of food and water. It is estimated that humans may consume thousand to millions of micro-plastic particles, equating to several milligrams per day. Prolonged exposure to micro-plastics and nano-plastics has been linked to negative effects on different living organisms, including neurotoxicity, gastrointestinal toxicity, nephrotoxicity, and hepatotoxicity, and developmental toxicities. The main purpose of this review is to explore the effect of micro-plastics and nano-plastics on the male and female reproductive system, as well as their offspring, and the associated mechanism implicated in the reproductive and developmental toxicities. Micro-plastics and nano-plastics have been shown to exert negative effects on the reproductive system of both male and female mammals and aquatic animals, including developmental impacts on gonads, gametes, embryo, and their subsequent generation. In addition, micro-plastics and nano-plastics impact the hypothalamic-pituitary axes, leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, poor sperm quality, diminishes ovarian ovulation and immune toxicity. This study discusses the so many different signaling pathways associated in the male and female reproductive and developmental toxicity induced by micro-plastics and nano-plastics.

Polystyrene microplastics enhance microcystin-LR-induced cardiovascular toxicity and oxidative stress in zebrafish embryos

The health risks associated with combined exposure to microplastics (MPs) and cyanobacteria toxins have gained increasing attention due to the large-scale prevalence of cyanobacterial blooms and accumulation of MPs in aquatic environments. Therefore, we explored the cardiovascular toxic effects of microcystin-LR (MC-LR, 1, 10, 100 μg/L) in the presence of 5 μm polystyrene microplastics (PS-MPs, 100 μg/L) and 80 nm polystyrene nanoplastics (PS-NPs, 100μg/L) in zebrafish models. Embryos were exposed to certain PS-MPs and PS-NPs conditions in water between 3 h post-fertilization (hpf) and 168 hpf. Compared to MC-LR alone, a significant decrease in heart rate was observed as well as notable pericardial edema in the MC-LR+PS-MPs/NPs groups. At the same time, sinus venosus and bulbus arteriosus (SV-BA) distances were significantly increased. Furthermore, the addition of PS-MPs/NPs caused thrombosis in the caudal vein and more severe vascular damage in zebrafish larvae compared to MC-LR alone. Our findings revealed that combined exposure to PS-NPs and MC-LR could significantly decreased the expression of genes associated with cardiovascular development (myh6, nkx2.5, tnnt2a, and vegfaa), ATPase (atp1a3b, atp1b2b, atp2a1l, atp2b1a, and atp2b4), and the calcium channel (cacna1ab and ryr2a) compared to exposure to MC-LR alone. In addition, co-exposure with PS-MPs/NPs exacerbated the MC-LR-induced reactive oxygen species (ROS) production, as well as the ROS-stimulated apoptosis and heightened inflammation. We also discovered that astaxanthin (ASTA) treatment partially attenuated these cardiovascular toxic effects. Our findings confirm that exposure to MC-LR and PS-MPs/NPs affects cardiovascular development through calcium signaling interference and ROS-induced cardiovascular cell apoptosis. This study highlights the potential environmental risks of the co-existence of MC-LR and PS-MPs/NPs for fetal health, particularly cardiovascular development.

Miro-mediated mitochondrial transport: A new dimension for disease-related abnormal cell metabolism?

Mitochondria are versatile and highly dynamic organelles found in eukaryotic cells that play important roles in a variety of cellular processes. The importance of mitochondrial transport in cell metabolism, including variations in mitochondrial distribution within cells and intercellular transfer, has grown in recent years. Several studies have demonstrated that abnormal mitochondrial transport represents an early pathogenic alteration in a variety of illnesses, emphasizing its significance in disease development and progression. Mitochondrial Rho GTPase (Miro) is a protein found on the outer mitochondrial membrane that is required for cytoskeleton-dependent mitochondrial transport, mitochondrial dynamics (fusion and fission), and mitochondrial Ca2+ homeostasis. Miro, as a critical regulator of mitochondrial transport, has yet to be thoroughly investigated in illness. This review focuses on recent developments in recognizing Miro as a crucial molecule in controlling mitochondrial transport and investigates its roles in diverse illnesses. It also intends to shed light on the possibilities of targeting Miro as a therapeutic method for a variety of diseases.

The impact of nanomaterials on autophagy across health and disease conditions

Autophagy, a catabolic process integral to cellular homeostasis, is constitutively active under physiological and stress conditions. The role of autophagy as a cellular defense response becomes particularly evident upon exposure to nanomaterials (NMs), especially environmental nanoparticles (NPs) and nanoplastics (nPs). This has positioned autophagy modulation at the forefront of nanotechnology-based therapeutic interventions. While NMs can exploit autophagy to enhance therapeutic outcomes, they can also trigger it as a pro-survival response against NP-induced toxicity. Conversely, a heightened autophagy response may also lead to regulated cell death (RCD), in particular autophagic cell death, upon NP exposure. Thus, the relationship between NMs and autophagy exhibits a dual nature with therapeutic and environmental interventions. Recognizing and decoding these intricate patterns are essential for pioneering next-generation autophagy-regulating NMs. This review delves into the present-day therapeutic potential of autophagy-modulating NMs, shedding light on their status in clinical trials, intervention of autophagy in the therapeutic applications of NMs, discusses the potency of autophagy for application as early indicator of NM toxicity.

Spatiotemporal development of the neuronal accumulation of amyloid precursor protein and the amyloid plaque formation in the brain of 3xTg-AD mice

The amyloid plaque is a hallmark of Alzheimer's disease. The accumulation of the amyloid precursor protein (APP) in the neuronal structure is assumed to lead to amyloid plaque formation through the excessive production of β-amyloid protein. To study the relationship between the neuronal accumulation of APP and amyloid plaque formation, we histologically analyzed their development in the different brain regions in 3xTg-AD mice, which express Swedish mutated APP (APPSWE) in the neurons. Observation throughout the brain revealed APPSWE-positive somata in the broad regions. Quantitative model analysis showed that the somatic accumulation of APPSWE developed firstly in the hippocampus from a very early age (<1 month) and proceeded slower in the isocortex. In line with this, the hippocampus was the first region to form amyloid plaques at the age of 9-12 months, while amyloid plaques were rarely observed in the isocortex. Females had more APPSWE-positive somata and plaques than males. Furthermore, amyloid plaques were observed in the lateral septum and pontine grey, which did not contain APPSWE-positive somata but only the APPSWE-positive fibers. These results suggested that neuronal accumulation of APPSWE, both in somatodendritic and axonal domains, is closely related to the formation of amyloid plaques.

Isoform-independent promotion of contractility and proliferation, and suppression of survival by with no lysine/K kinases in prostate stromal cells

With no lysine/K kinases (WNKs) promote vasocontraction and vascular smooth muscle cell proliferation. In the prostate, smooth muscle contraction and growth may be critical for the development and medical treatment of voiding symptoms in benign prostatic hyperplasia. Here, we examined the effects of isoform-specific WNK silencing and of the WNK inhibitor WNK463 on growth-related functions and contraction in prostate stromal cells, and in human prostate tissues. Impacts of WNK silencing by transfection of cultured stromal cells with isoform-specific siRNAs were qualitatively and quantitatively similar for each WNK isoform. Effects of silencing were largest on cell death (3-5 fold increase in annexin V-positive/7-AAD-positive cells), on proliferation rate, Ki-67 mRNA expression and actin organization (reduced around two-thirds). Contraction in matrix contraction assays and viability were reduced to a lower degree (approximately half), but again to a similar extent for each WNK isoform. Effects of silencing were quantitatively and qualitatively reproduced by 10 μM WNK463, while 1 μM still induced cell death and breakdown in actin organization, without affecting proliferation or viability. Using 500 nM and 10 μM, WNK463 partly inhibited neurogenic and U46619-induced contractions of human prostate tissues (around half), while inhibition of α1-adrenergic contractions (around half) was limited to 10 μM. All four WNK isoforms suppress cell death and promote proliferation in prostate stromal cells. WNK-driven contraction of stromal cells appears possible, even though to a limited extent. Outcomes of isoform-specific WNK silencing can be fully reproduced by WNK463, including inhibition of smooth muscle contraction in human prostate tissues, but require high concentrations.

Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

Microplastics (MPs) and nanoplastics (NPs) have become hazardous materials due to the massive amount of plastic waste and disposable masks, but their specific health effects remain uncertain. In this study, fluorescence-labeled polystyrene NPs (PS-NPs) were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in vivo. Interestingly, whole-body imaging found that PS-NPs accumulated in the testes of mice. Therefore, the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice, and their mechanisms, were investigated. After oral exposure to PS-NPs, their spermatogenesis was affected and the spermatogenic cells were damaged. The spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing (RNA-seq) to determine the toxic mechanisms; a ferroptosis pathway was found after PS-NP exposure. The phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1 (Fer-1), and it was also found that nuclear factor erythroid 2-related factor 2 (Nrf2) played an important role in spermatogenic cell ferroptosis induced by PS-NPs. Finally, it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive toxicity. This study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

The adverse effects of developmental exposure to polystyrene nanoparticles on cognitive function in weaning rats and the protective role of trihydroxy phenolacetone

Polystyrene nanoplastic(PS-NP) can originate from sources such as plastic waste and industrial wastewater and have been shown to have deleterious effects on abnormal neurobehaviors. However, evidence regarding the health impacts, biological mechanisms, and treatment strategies underlying developmental exposure to low dose PS-NP is still lacking. This study aimed to fill this knowledge gap by administering low doses of PS-NP(50 and 100 μg/L) to weaning rats for 4 consecutive weeks. Behavioral and morphological experiments were performed to evaluate hippocampal damage, and transcriptomics and Assay for Transposase Accessible Chromatin with hight-throughput sequencing(ATAC) analyses were conducted to identify potential key targets. Additionally, Connectivity Map(CMap) database, Limited proteolysis-mass spectrometry(LiP-SMap), and molecular-protein docking were used to examine potential phytochemicals with therapeutic effects on key targets. The results indicated that developmental exposure to PS-NP can induce hippocampal impairment and aberrant neurobehaviors in adulthood. Multi-omics analyses consistently showed that apoptosis-related signaling pathways were sensitive to PS-NP exposure, and mitogen-activated protein kinase 3(Mapk3) was identified as the core gene by the gene network, which was further validated in vitro experiments. The CMap database provided a series of phytochemicals that might regulate Mapk3 expression, and trihydroxy-phenolacetone(THP) was found to have directly binding sites with Mapk3 through LiP-SMap and molecular docking analysis. Furthermore, THP administration could significantly alleviate apoptosis induced by PS-NP exposure in primary hippocampal cells through down-regulation of Mapk3. These findings suggested that developmental exposure to PS-NP has adverse effects on cognitive function and that THP can alleviate these effects by directly binding to Mapk3.

Effect of nanobubbles on the mobilization of microplastics in shorelines subject to seawater infiltration

The widespread presence of microplastics (MPs) in the ocean has varying degrees of impact on ecosystems and even human health. Coastal tidal zones are crucial in controlling the movement of MPs, which are influenced by waves and tidal forces. Meanwhile, natural nanobubbles (NBs) in the ocean can affect the hydrodynamic properties of the tidal zone. The mobilization of MPs in coastal tidal zones under the effect of NBs has been less studied. In this study, we explored natural NBs' influence on the mobilization of MPs in shorelines subject to seawater infiltration. Using glass beads as a substrate, a coastal porous environment was constructed through column experiments, and the pump-controlled water flow was used to study the transport of MPs subject to seawater movement within the substrate. The infiltration of MPs under continuous and transient conditions, as well as the upward transport induced by flood tide, were considered. The role of salinity in the interactions between NBs, MPs, and substrates was evaluated. Salinity altered the energy barriers between particles, which in turn affected the movement of MPs within the substrate. In addition, hydrophilic MPs were more likely to infiltrate within the substrate and had different movement patterns under continuous and transient flow conditions. The motion of the MPs within the substrate varied with flow rate, and NBs limited the vertical movement of MPs in the tidal zone. It was also observed that NBs adsorbed readily onto substrates, altering the surface properties of substrates, particularly their ability to attach and detach from other substances.

Miro GTPases at the Crossroads of Cytoskeletal Dynamics and Mitochondrial Trafficking

Miro GTPases are key components in the machinery responsible for transporting mitochondria and peroxisomes along microtubules, and also play important roles in regulating calcium homeostasis and organizing contact sites between mitochondria and the endoplasmic reticulum. Moreover, Miro GTPases have been shown to interact with proteins that actively regulate cytoskeletal organization and dynamics, suggesting that these GTPases participate in organizing cytoskeletal functions and organelle transport. Derailed mitochondrial transport is associated with neuropathological conditions such as Parkinson's and Alzheimer's diseases. This review explores our recent understanding of the diverse roles of Miro GTPases under cytoskeletal control, both under normal conditions and during the course of human diseases such as neuropathological disorders.

Impact of Micro- and Nano-Plastics on Human Intestinal Organoid-Derived Epithelium

The development of patient-derived intestinal organoids represents an invaluable model for simulating the native human intestinal epithelium. These stem cell-rich cultures outperform commonly used cell lines like Caco-2 and HT29-MTX in reflecting the cellular diversity of the native intestinal epithelium after differentiation. In our recent study examining the effects of polystyrene (PS), microplastics (MPs), and nanoplastics (NPs), widespread pollutants in our environment and food chain, on the human intestinal epithelium, these organoids have been instrumental in elucidating the absorption mechanisms and potential biological impacts of plastic particles. Building on previously established protocols in human intestinal organoid culture, we herein detail a streamlined protocol for the cultivation, differentiation, and generation of organoid-derived monolayers. This protocol is tailored to generate monolayers incorporating microfold cells (M cells), key for intestinal particle uptake but often absent in current in vitro models. We provide validated protocols for the characterization of MPs/NPs via scanning electron microscopy (SEM) for detailed imaging and their introduction to intestinal epithelial monolayer cells via confocal immunostaining. Additionally, protocols to test the impacts of MP/NP exposure on the functions of the intestinal barrier using transendothelial electrical resistance (TEER) measurements and assessing inflammatory responses using cytokine profiling are detailed. Overall, our protocols enable the generation of human intestinal organoid monolayers, complete with the option of including or excluding M cells, offering crucial techniques for observing particle uptake and identifying inflammatory responses in intestinal epithelial cells to advance our knowledge of the potential effects of plastic pollution on human gut health. These approaches are also amendable to the study of other gut-related chemical and biological exposures and physiological responses due to the robust nature of the systems. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Human intestinal organoid culture and generation of monolayers with and without M cells Support Protocol 1: Culture of L-WRN and production of WRN-conditioned medium Support Protocol 2: Neuronal cell culture and integration into intestinal epithelium Support Protocol 3: Immune cell culture and integration into intestinal epithelium Basic Protocol 2: Scanning electron microscopy: sample preparation and imaging Basic Protocol 3: Immunostaining and confocal imaging of MP/NP uptake in organoid-derived monolayers Basic Protocol 4: Assessment of intestinal barrier function via TEER measurements Basic Protocol 5: Cytokine profiling using ELISA post-MP/NP exposure.

Microplastics role in cell migration and distribution during cancer cell division

Amidst the global plastic pollution crisis, the gastrointestinal tract serves as the primary entry point for daily exposure to micro- and nanoplastics. We investigated the complex dynamics between polystyrene micro- and nanoplastics (PS-MNPs) and four distinct human colorectal cancer cell lines (HT29, HCT116, SW480, and SW620). Our findings revealed a significant size- and concentration dependent uptake of 0.25, 1, and 10 μm PS-MNPs across all cell lines, with HCT116 cells exhibiting the highest uptake rates. During cell division, particles were distributed between mother and daughter cells. Interestingly, we observed no signs of elimination from the cells. Short-term exposure to 0.25 μm particles significantly amplified cell migration, potentially leading to pro-metastatic effects. Particles demonstrated high persistence in 2D and 3D cultures, and accumulation in non-proliferating parts of spheroids, without interfering with cell proliferation or division. Our study unveils the disturbing fact of the persistence and bioaccumulation of MNPs in colorectal cancer cell lines, key toxicological traits under REACH (Regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals). Our observations underscore the potential of MNPs as hidden catalysts for tumor progression, particularly through enhancing cell migration and possibly fueling metastasis - a finding that sheds light on a significant and previously underexplored area of concern.

Aged polystyrene microplastics exacerbate alopecia associated with tight junction injuries and apoptosis via oxidative stress pathway in skin

Microplastics (MPs) are pervasive pollutants in the natural environment and contribute to increased levels of illness in both animals and humans. However, thespecific impacts of MPs on skin damage and alopeciaare not yet well understood. In this study, we have examined the effects of two types of polystyrene MPs (pristine and aged) on skin and hair follicle damage in mice. UV irradiation changed the chemical and physical properties of the aged MPs, including functional groups, surface roughness, and contact angles. In both in vivo and in vitro experiments, skin and cell injuries related to oxidative stress, apoptosis, tight junctions (TJs), alopecia, mitochondrial dysfunction, and other damages were observed. Mechanistically, MPs and aged MPs can induce TJs damage via the oxidative stress pathway and inhibition of antioxidant-related proteins, and this can lead to alopecia. The regulation of cell apoptosis was also observed, and this is involved in the ROS-mediated mitochondrial signaling pathway. Importantly, aged MPs showed exacerbated toxicity, which may be due to their elevated surface irregularities and altered chemical compositions. Collectively, this study suggests a potential therapeutic approach for alopecia and hair follicle damage caused by MPs pollution.

Molecular hybridization: a powerful tool for multitarget drug discovery

INTRODUCTION

The current drug discovery paradigm of 'one drug, multiple targets' has gained attention from both the academic medicinal chemistry community and the pharmaceutical industry. This is in response to the urgent need for effective agents to treat multifactorial chronic diseases. The molecular hybridization strategy is a useful tool that has been widely explored, particularly in the last two decades, for the design of multi-target drugs.

AREAS COVERED

This review examines the current state of molecular hybridization in guiding the discovery of multitarget small molecules. The article discusses the design strategies and target selection for a multitarget polypharmacology approach to treat various diseases, including cancer, Alzheimer's disease, cardiac arrhythmia, endometriosis, and inflammatory diseases.

EXPERT OPINION

Although the examples discussed highlight the importance of molecular hybridization for the discovery of multitarget bioactive compounds, it is notorious that the literature has focused on specific classes of targets. This may be due to a deep understanding of the pharmacophore features required for target binding, making targets such as histone deacetylases and cholinesterases frequent starting points. However, it is important to encourage the scientific community to explore diverse combinations of targets using the molecular hybridization strategy.

In Vivo Tissue Distribution of Polystyrene or Mixed Polymer Microspheres and Metabolomic Analysis after Oral Exposure in Mice

BACKGROUND

Global plastic use has consistently increased over the past century with several different types of plastics now being produced. Much of these plastics end up in oceans or landfills leading to a substantial accumulation of plastics in the environment. Plastic debris slowly degrades into microplastics (MPs) that can ultimately be inhaled or ingested by both animals and humans. A growing body of evidence indicates that MPs can cross the gut barrier and enter into the lymphatic and systemic circulation leading to accumulation in tissues such as the lungs, liver, kidney, and brain. The impacts of mixed MPs exposure on tissue function through metabolism remains largely unexplored.

OBJECTIVES

This study aims to investigate the impacts of polymer microspheres on tissue metabolism in mice by assessing the microspheres ability to translocate across the gut barrier and enter into systemic circulation. Specifically, we wanted to examine microsphere accumulation in different organ systems, identify concentration-dependent metabolic changes, and evaluate the effects of mixed microsphere exposures on health outcomes.

METHODS

To investigate the impact of ingested microspheres on target metabolic pathways, mice were exposed to either polystyrene (5 μ m ) microspheres or a mixture of polymer microspheres consisting of polystyrene (5 μ m ), polyethylene (1 - 4 μ m ), and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid) (5 μ m ). Exposures were performed twice a week for 4 weeks at a concentration of either 0, 2, or 4 mg / week via oral gastric gavage. Tissues were collected to examine microsphere ingress and changes in metabolites.

RESULTS

In mice that ingested microspheres, we detected polystyrene microspheres in distant tissues including the brain, liver, and kidney. Additionally, we report on the metabolic differences that occurred in the colon, liver, and brain, which showed differential responses that were dependent on concentration and type of microsphere exposure.

DISCUSSION

This study uses a mouse model to provide critical insight into the potential health implications of the pervasive issue of plastic pollution. These findings demonstrate that orally consumed polystyrene or mixed polymer microspheres can accumulate in tissues such as the brain, liver, and kidney. Furthermore, this study highlights concentration-dependent and polymer type-specific metabolic changes in the colon, liver, and brain after plastic microsphere exposure. These results underline the mobility within and between biological tissues of MPs after exposure and emphasize the importance of understanding their metabolic impact. https://doi.org/10.1289/EHP13435.

Are you drowned in microplastic pollution? A brief insight on the current knowledge for early career researchers developing novel remediation strategies

Microplastics (MPs) composed of different polymers with various shapes, within a vast granulometric distribution (1 μm - 5 mm) and with a wide variety of physicochemical surface and bulk characteristics spiral around the globe, with different atmospheric, oceanic, cryospheric, and terrestrial residence times, while interacting with other pollutants and biota. The challenges of microplastic pollution are related to the complex relationships between the microplastic generation mechanisms (physical, chemical, and biological), their physicochemical properties, their interactions with other pollutants and microorganisms, the changes in their properties with aging, and their small sizes that facilitate their diffusion and transportation between the air, water, land, and biota, thereby promoting their ubiquity. Early career researchers (ERCs) constitute an essential part of the scientific community committed to overcoming the challenges of microplastic pollution with their new ideas and innovative scientific perspectives for the development of remediation technologies. However, because of the enormous amount of scientific information available, it may be difficult for ERCs to determine the complexity of this environmental issue. This mini-review aims to provide a quick and updated overview of the essential insights of microplastic pollution to ERCs to help them acquire the background needed to develop highly innovative physical, chemical, and biological remediation technologies, as well as valorization proposals and environmental education and awareness campaigns. Moreover, the recommendations for the development of holistic microplastic pollution remediation strategies presented here can help ERCs propose technologies considering the environmental, social, and practical dimensions of microplastic pollution while fulfilling the current government policies to manage this plastic waste.

Micro(nano)plastics and Their Potential Impact on Human Gut Health: A Narrative Review

Microplastics and nanoplastics (MNPs) are becoming an increasingly severe global problem due to their widespread distribution and complex impact on living organisms. Apart from their environmental impact, the effects of MNPs on living organisms have also continued to attract attention. The harmful impact of MNPs has been extensively documented in marine invertebrates and larger marine vertebrates like fish. However, the research on the toxicity of these particles on mammals is still limited, and their possible effects on humans are poorly understood. Considering that MNPs are commonly found in food or food packaging, humans are primarily exposed to them through ingestion. It would be valuable to investigate the potential harmful effects of these particles on gut health. This review focuses on recent research exploring the toxicological impacts of micro- and nanoplastics on the gut, as observed in human cell lines and mammalian models. Available data from various studies indicate that the accumulation of MNPs in mammalian models and human cells may result in adverse consequences, in terms of epithelial toxicity, immune toxicity, and the disruption of the gut microbiota. The paper also discusses the current research limitations and prospects in this field, aiming to provide a scientific basis and reference for further studies on the toxic mechanisms of micro- and nanoplastics.

Colloidal Engineering of Microplastic Capture with Biodegradable Soft Dendritic "Microcleaners"

The introduction of colloidal principles that enable efficient microplastic collection from aquatic environments is a goal of great environmental importance. Here, we present a novel method of microplastic (MP) collection using biodegradable hydrogel soft dendritic colloids (hSDCs). These dendritic colloids have abundant nanofibrils and a large surface area, which provide an abundance of interfacial interactions and excellent networking capabilities, allowing for the capture of plastic particles and other contaminants. Here, we show how the polymer composition and morphology of the hSDCs can impact the capture of microplastics modeled by latex microbeads. Additionally, we use colloidal DLVO theory to interpret the capture efficiencies of microbeads of different sizes and surface functional groups. The results demonstrate the microplastic remediation efficiency of hydrogel dendricolloids and highlight the primary factors involved in the microbead interactions and adsorption. On a practical level, the results show that the development of environmentally benign microcleaners based on naturally sourced materials could present a sustainable solution for microplastic cleanup.

Association of urinary chlorpyrifos, paraquat, and cyproconazole levels with the severity of fatty liver based on MRI

BACKGROUND

The objective of this study was to detect the urinary levels of chlorpyrifos, paraquat, and cyproconazole in residents living in Fuyang City and to analyze the correlation between these urinary pesticides levels and the severity of fatty liver disease (FLD).

METHODS

All participants' fat fraction (FF) values were recorded by MRI (Magnetic resonance imaging). First-morning urine samples were collected from 53 participants from Fuyang Peoples'Hospital. The levels of three urinary pesticides were measured using β-glucuronidase hydrolysis followed by a. The results were analyzed by using Pearson correlation analysis and binary logistic regression analysis to reveal the correlation between three urinary pesticides and the severity of fatty liver.

RESULTS

53 individuals were divided into 3 groups based on the results from MRI, with 20 cases in the normal control group, 16 cases in the mild fatty liver group, and 17 cases in the moderate and severe fatty liver group. Urinary chlorpyrifos level was increased along with the increase of the severity of fatty liver. Urinary paraquat level was significantly higher both in the low-grade fatty liver group and moderate & serve grade fatty liver group compared with the control group. No significant differences in urinary cyproconazole levels were observed among the three groups. Furthermore, urinary chlorpyrifos and paraquat levels were positively correlated with FF value. And chlorpyrifos was the risk factor that may be involved in the development of FLD and Receiver Operating Characteristic curve (ROC curve) analysis showed that chlorpyrifos and paraquat may serve as potential predictors of FLD.

CONCLUSION

The present findings indicate urinary chlorpyrifos and paraquat were positively correlated with the severity of fatty liver. Moreover, urinary chlorpyrifos and paraquat have the potential to be considered as the predictors for development of FLD. Thus, this study may provide a new perspective from the environmental factors for the diagnosis, prevention, and treatment of FLD.

The polyglutamine domain is the primary driver of seeding in huntingtin aggregation

Huntington's Disease (HD) is a fatal, neurodegenerative disease caused by aggregation of the huntingtin protein (htt) with an expanded polyglutamine (polyQ) domain into amyloid fibrils. Htt aggregation is modified by flanking sequences surrounding the polyQ domain as well as the binding of htt to lipid membranes. Upon fibrillization, htt fibrils are able to template the aggregation of monomers into fibrils in a phenomenon known as seeding, and this process appears to play a critical role in cell-to-cell spread of HD. Here, exposure of C. elegans expressing a nonpathogenic N-terminal htt fragment (15-repeat glutamine residues) to preformed htt-exon1 fibrils induced inclusion formation and resulted in decreased viability in a dose dependent manner, demonstrating that seeding can induce toxic aggregation of nonpathogenic forms of htt. To better understand this seeding process, the impact of flanking sequences adjacent to the polyQ stretch, polyQ length, and the presence of model lipid membranes on htt seeding was investigated. Htt seeding readily occurred across polyQ lengths and was independent of flanking sequence, suggesting that the structured polyQ domain within fibrils is the key contributor to the seeding phenomenon. However, the addition of lipid vesicles modified seeding efficiency in a manner suggesting that seeding primarily occurs in bulk solution and not at the membrane interface. In addition, fibrils formed in the presence of lipid membranes displayed similar seeding efficiencies. Collectively, this suggests that the polyQ domain that forms the amyloid fibril core is the main driver of seeding in htt aggregation.

Exposure to high dose of polystyrene nanoplastics causes trophoblast cell apoptosis and induces miscarriage

BACKGROUND

With rapid increase in the global use of various plastics, microplastics (MPs) and nanoplastics (NPs) pollution and their adverse health effects have attracted global attention. MPs have been detected out in human body and both MPs and NPs showed female reproductive toxicological effects in animal models. Miscarriage (abnormal early embryo loss), accounting for 15-25% pregnant women worldwide, greatly harms human reproduction. However, the adverse effects of NPs on miscarriage have never been explored.

RESULTS

In this study, we identified that polystyrene (PS) plastics particles were present in women villous tissues. Their levels were higher in villous tissues of unexplained recurrent miscarriage (RM) patients vs. healthy control (HC) group. Furthermore, mouse assays further confirmed that exposure to polystyrene nanoplastics (PS-NPs, 50 nm in diameter, 50 or 100 mg/kg) indeed induced miscarriage. In mechanism, PS-NPs exposure (50, 100, 150, or 200 µg/mL) increased oxidative stress, decreased mitochondrial membrane potential, and increased apoptosis in human trophoblast cells by activating Bcl-2/Cleaved-caspase-2/Cleaved-caspase-3 signaling through mitochondrial pathway. The alteration in this signaling was consistent in placental tissues of PS-NPs-exposed mouse model and in villous tissues of unexplained RM patients. Supplement with Bcl-2 could efficiently suppress apoptosis in PS-NPs-exposed trophoblast cells and reduce apoptosis and alleviate miscarriage in PS-NPs-exposed pregnant mouse model.

CONCLUSIONS

Exposure to PS-NPs activated Bcl-2/Cleaved-caspase-2/Cleaved-caspase-3, leading to excessive apoptosis in human trophoblast cells and in mice placental tissues, further inducing miscarriage.

The potential impact of nano- and microplastics on human health: Understanding human health risks

Plastics are used all over the world. Unfortunately, due to limited biodegradation, plastics cause a significant level of environmental pollution. The smallest recognized to date are termed nanoplastics (1 nm [nm] up to 1 μm [μm]) and microplastics (1 μm-5 mm). These nano- and microplastics can enter the human body through the respiratory system via inhalation, the digestive tract via consumption of contaminated food and water, or penetration through the skin via cosmetics and clothes contact. Bioaccumulation of plastics in the human body can potentially lead to a range of health issues, including respiratory disorders like lung cancer, asthma and hypersensitivity pneumonitis, neurological symptoms such as fatigue and dizziness, inflammatory bowel disease and even disturbances in gut microbiota. Most studies to date have confirmed that nano- and microplastics can induce apoptosis in cells and have genotoxic and cytotoxic effects. Understanding the cellular and molecular mechanisms of plastics' actions may help extrapolate the risks to humans. The article provides a comprehensive review of articles in databases regarding the impact of nano- and microplastics on human health. The review included retrospective studies and case reports of people exposed to nanoplastics and microplastics. This research highlights the need for further research to fully understand the extent of the impact of plastics on human health.

Influence of the polymer type of a microplastic challenge on the reaction of murine cells

Due to global pollution derived from plastic waste, the research on microplastics is of increasing public interest. Until now, most studies addressing the effect of microplastic particles on vertebrate cells have primarily utilized polystyrene particles (PS). Other studies on polymer microparticles made, e.g., of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), or poly (ethylene terephthalate) (PET), cannot easily be directly compared to these PS studies, since the used microparticles differ widely in size and surface features. Here, effects caused by pristine microparticles of a narrow size range between 1 - 4 µm from selected conventional polymers including PS, PE, and PVC, were compared to those of particles made of polymers derived from biological sources like polylactic acid (PLA), and cellulose acetate (CA). The microparticles were used to investigate cellular uptake and assess cytotoxic effects on murine macrophages and epithelial cells. Despite differences in the particles' properties (e.g. ζ-potential and surface morphology), macrophages were able to ingest all tested particles, whereas epithelial cells ingested only the PS-based particles, which had a strong negative ζ-potential. Most importantly, none of the used model polymer particles exhibited significant short-time cytotoxicity, although the general effect of environmentally relevant microplastic particles on organisms requires further investigation.

Rab11 suppresses head and neck carcinoma by regulating EGFR and EpCAM exosome secretion

OBJECTIVES

Rab11(Rab11a and Rab11b) localizes primarily along recycling endosomes in cells and is involved in various intracellular trafficking processes, including membrane receptor recycling and secretion of exosomes or small extracellular vesicles (EVs). Although Rab11 is closely associated with the progression and metastasis of various cancer types, little is known about Rab11' role in head and neck squamous cell carcinoma (HNSCC). In this study, we investigated the roles of Rab11a and Rab11b in HNSCC.

METHODS

The clinical significance of Rab11 expression in HNSCC was investigated using a public database and tissue microarray analysis. Stable cell lines with loss and gain of Rab11a or Rab11b were originally established to investigate their roles in the proliferative, migratory, and invasive capabilities of HNSCC cells.

RESULTS

Database analysis revealed a significant association between Rab11b mRNA expression and a favorable patient survival rate in HNSCC. Tissue microarray analysis revealed that Rab11b expression was the highest in normal tissues and gradually decreased across the stages of HNSCC progression. Overexpression of Rab11a or Rab11b resulted in a decrease in epidermal growth factor receptor (EGFR), Epithelial cell adhesion molecule (EpCAM) exosome secretion, and the migratory and invasive potential of HNSCC cells. The knockdown of Rab11a or Rab11b increased EpCAM/CD9 exosome secretion in addition to the migratory and invasive potential of HNSCC cells.

CONCLUSIONS

Rab11 suppresses HNSCC by regulating EGFR recycling and EpCAM exosome secretion in HNSCC cells. Our results indicate that Rab11b is a superior prognostic indicator of HNSCC and holds promise for developing novel therapeutic strategies.

Cerebral neurotoxicity of amino-modified polystyrene nanoplastics in mice and the protective effects of functional food Camellia pollen

Accumulating evidence suggests that nanoplastics contribute to an increased risk of brain damage, however, the precise underlying mechanisms remain unclear. Here, we subjected mice to long-term exposure to amino-modified polystyrene nanoplastics (APS-NPs). These nanoplastics were detected in the mouse brain; coupled with the observed upregulation of Alzheimer's disease-associated genes (APP and MAPT). To further explore nanoplastic damage mechanisms and the corresponding protective strategies against these mechanisms in vitro, we used hCMEC/D3 and HT22 cells. Results showed that APS-NPs disrupted tight junction proteins (Occludin and ZO-1) via TLR2/MMP9 axis, resulting in blood-brain barrier permeation; this was significantly mitigated by functional food Camellia pollen treatment. APS-NPs initiated iNOS and nNOS upregulation within neurons resulting in Sirtuin 1 deacetylase inactivation and CBP acetyltransferase stimulation, ultimately leading to Ac-Tau formation. This process was attenuated by Camellia pollen, which also ameliorated the APS-NPs-induced neuronal apoptosis mediated by the p53/Bax/Bcl-2 axis. Network pharmacology analysis of Camellia pollen offered a further theoretical understanding of its potential applications in preventing and treating nervous system disorders, such as Alzheimer's disease. This study established that Camellia pollen protects the brain against APS-NPs-mediated blood-brain barrier damage and alleviates neuronal apoptosis and Alzheimer's disease-like neurotoxicity. This study elucidates the mechanisms underlying polystyrene-induced brain damage and can be used to inform future prevention and treatment strategies.

The potential toxicity of microplastics on human health

Microplastics are plastic particles, films, and fibers with a diameter of < 5 mm. Given their long-standing existence in the environment and terrible increase in annual emissions, concerns were raised about the potential health risk of microplastics on human beings. In particular, the increased consumption of masks during the COVID-19 pandemic has dramatically increased human contact with microplastics. To date, the emergence of microplastics in the human body, such as feces, blood, placenta, lower airway, and lungs, has been reported. Related toxicological investigations of microplastics were gradually increased. To comprehensively illuminate the interplay of microplastic exposure and human health, we systematically reviewed the updated toxicological data of microplastics and summarized their mode of action, adverse effects, and toxic mechanisms. The emerging critical issues in the current toxicological investigations were proposed and discussed. Our work would facilitate a better understanding of MPs-induced health hazards for toxicological evaluation and provide helpful information for regulatory decisions.

Using Rapid Prototyping to Develop a Cell-Based Platform with Electrical Impedance Sensor Membranes for In Vitro RPMI2650 Nasal Nanotoxicology Monitoring

Due to advances in additive manufacturing and prototyping, affordable and rapid microfluidic sensor-integrated assays can be fabricated using additive manufacturing, xurography and electrode shadow masking to create versatile platform technologies aimed toward qualitative assessment of acute cytotoxic or cytolytic events using stand-alone biochip platforms in the context of environmental risk assessment. In the current study, we established a nasal mucosa biosensing platform using RPMI2650 mucosa cells inside a membrane-integrated impedance-sensing biochip using exclusively rapid prototyping technologies. In a final proof-of-concept, we applied this biosensing platform to create human cell models of nasal mucosa for monitoring the acute cytotoxic effect of zinc oxide reference nanoparticles. Our data generated with the biochip platform successfully monitored the acute toxicity and cytolytic activity of 6 mM zinc oxide nanoparticles, which was non-invasively monitored as a negative impedance slope on nasal epithelial models, demonstrating the feasibility of rapid prototyping technologies such as additive manufacturing and xurography for cell-based platform development.

Microplastics as carriers of toxic pollutants: Source, transport, and toxicological effects

Microplastic pollution has emerged as a new environmental concern due to our reliance on plastic. Recent years have seen an upward trend in scholarly interest in the topic of microplastics carrying contaminants; however, the available review studies have largely focused on specific aspects of this issue, such as sorption, transport, and toxicological effects. Consequently, this review synthesizes the state-of-the-art knowledge on these topics by presenting key findings to guide better policy action toward microplastic management. Microplastics have been reported to absorb pollutants such as persistent organic pollutants, heavy metals, and antibiotics, leading to their bioaccumulation in marine and terrestrial ecosystems. Hydrophobic interactions are found to be the predominant sorption mechanism, especially for organic pollutants, although electrostatic forces, van der Waals forces, hydrogen bonding, and pi-pi interactions are also noteworthy. This review reveals that physicochemical properties of microplastics, such as size, structure, and functional groups, and environmental compartment properties, such as pH, temperature, and salinity, influence the sorption of pollutants by microplastic. It has been found that microplastics influence the growth and metabolism of organisms. Inadequate methods for collection and analysis of environmental samples, lack of replication of real-world settings in laboratories, and a lack of understanding of the sorption mechanism and toxicity of microplastics impede current microplastic research. Therefore, future research should focus on filling in these knowledge gaps.

A comprehensive review on the source, ingestion route, attachment and toxicity of microplastics/nanoplastics in human systems

Microplastics (MPs)/nanoplastics (NPs) are widely found in the natural environment, including soil, water and the atmosphere, which are essential for human survival. In the recent years, there has been a growing concern about the potential impact of MPs/NPs on human health. Due to the increasing interest in this research and the limited number of studies related to the health effects of MPs/NPs on humans, it is necessary to conduct a systematic assessment and review of their potentially toxic effects on human organs and tissues. Humans can be exposed to microplastics through ingestion, inhalation and dermal contact, however, ingestion and inhalation are considered as the primary routes. The ingested MPs/NPs mainly consist of plastic particles with a particle size ranging from 0.1 to 1 μm, that distribute across various tissues and organs within the body, which in turn have a certain impact on the nine major systems of the human body, especially the digestive system and respiratory system, which are closely related to the intake pathway of MPs/NPs. The harmful effects caused by MPs/NPs primarily occur through potential toxic mechanisms such as induction of oxidative stress, generation of inflammatory responses, alteration of lipid metabolism or energy metabolism or expression of related functional factors. This review can help people to systematically understand the hazards of MPs/NPs and related toxicity mechanisms from the level of nine biological systems. It allows MPs/NPs pollution to be emphasized, and it is also hoped that research on their toxic effects will be strengthened in the future.

Intracellular Protein Adsorption Behavior and Biological Effects of Polystyrene Nanoplastics in THP-1 Cells

Micro(nano)plastics (MNPs) are emerging pollutants that can adsorb pollutants in the environment and biological molecules and ultimately affect human health. However, the aspects of adsorption of intracellular proteins onto MNPs and its biological effects in cells have not been investigated to date. The present study revealed that 100 nm polystyrene nanoplastics (NPs) could be internalized by THP-1 cells and specifically adsorbed intracellular proteins. In total, 773 proteins adsorbed onto NPs with high reliability were identified using the proteomics approach and analyzed via bioinformatics to predict the route and distribution of NPs following cellular internalization. The representative proteins identified via the Kyoto Encyclopedia of Genes and Genomes pathway analysis were further investigated to characterize protein adsorption onto NPs and its biological effects. The analysis revealed that NPs affect glycolysis through pyruvate kinase M (PKM) adsorption, trigger the unfolded protein response through the adsorption of ribophorin 1 (RPN1) and heat shock 70 protein 8 (HSPA8), and are chiefly internalized into cells through clathrin-mediated endocytosis with concomitant clathrin heavy chain (CLTC) adsorption. Therefore, this work provides new insights and research strategies for the study of the biological effects caused by NPs.

Airborne Nanoplastics Exposure Inducing Irreversible Glucose Increase and Complete Hepatic Insulin Resistance

As an emerging type of pollutant, microplastics have become a global environmental problem. Approximately, a fifth of the global burden of type 2 diabetes can be attributed to air particulate pollution. However, scientific knowledge remains limited about the effects of airborne nanoplastics (NPs) exposure on metabolic diseases. In this experiment, a whole-body exposure system was used to simulate the real atmospheric environment, and three exposure concentrations combined with the actual environmental concentration were selected to explore the effects of airborne NPs on metabolic diseases. Based on histological analyses, metabolic studies, gene expression, metabolites, and molecular signaling analyses, mice exposed to airborne NPs were observed to show a phenotype of systemic inflammation and complete insulin resistance featuring excessive drinking and eating, weight loss, elevated blood glucose, and decreased triglyceride levels. After airborne NPs exposure, mice were intolerant to glucose and tolerant to insulin. In addition, airborne NPs exposure could result in long-term irreversible hyperglycemia. Together, the research findings provide a strong basis for understanding the hazards of airborne nanopollution on metabolic disorders.

Influence of polyethylene terephthalate (PET) microplastic on selected active substances in the intramural neurons of the porcine duodenum

BACKGROUND

Currently, society and industry generate huge amounts of plastics worldwide. The ubiquity of microplastics is obvious, but its impact on the animal and human organism remains not fully understood. The digestive tract is one of the first barriers between pathogens and xenobiotics and a living organism. Its proper functioning is extremely important in order to maintain homeostasis. The aim of this study was to determine the effect of microplastic on enteric nervous system and histological structure of swine duodenum. The experiment was carried out on 15 sexually immature gilts, approximately 8 weeks old. The animals were randomly divided into 3 study groups (n = 5/group). The control group received empty gelatin capsules once a day for 28 days, the first research group received daily gelatin capsules with polyethylene terephthalate (PET) particles as a mixture of particles of various sizes (maximum particle size 300 µm) at a dose of 0.1 g/animal/day. The second study group received a dose ten times higher-1 g/animal/day.

RESULTS

A dose of 1 g/day/animal causes more changes in the enteric nervous system and in the histological structure of duodenum. Statistically significant differences in the expression of cocaine and amphetamine regulated transcript, galanin, neuronal nitric oxide synthase, substance P, vesicular acetylcholine transporter and vasoactive intestinal peptide between control and high dose group was noted. The histopathological changes were more frequently observed in the pigs receiving higher dose of PET.

CONCLUSION

Based on this study it may be assumed, that oral intake of microplastic might have potential negative influence on digestive tract, but it is dose-dependent.

Recent progress and future directions of the research on nanoplastic-induced neurotoxicity

Many types of plastic products, including polystyrene, have long been used in commercial and industrial applications. Microplastics and nanoplastics, plastic particles derived from these plastic products, are emerging as environmental pollutants that can pose health risks to a wide variety of living organisms, including humans. However, it is not well understood how microplastics and nanoplastics affect cellular functions and induce stress responses. Humans can be exposed to polystyrene-microplastics and polystyrene-nanoplastics through ingestion, inhalation, or skin contact. Most ingested plastics are excreted from the body, but inhaled plastics may accumulate in the lungs and can even reach the brain via the nose-to-brain route. Small-sized polystyrene-nanoplastics can enter cells by endocytosis, accumulate in the cytoplasm, and cause various cellular stresses, such as inflammation with increased pro-inflammatory cytokine production, oxidative stress with generation of reactive oxygen species, and mitochondrial dysfunction. They induce autophagy activation and autophagosome formation, but autophagic flux may be impaired due to lysosomal dysfunction. Unless permanently exposed to polystyrene-nanoplastics, they can be removed from cells by exocytosis and subsequently restore cellular function. However, neurons are very susceptible to this type of stress, thus even acute exposure can lead to neurodegeneration without recovery. This review focuses specifically on recent advances in research on polystyrene-nanoplastic-induced cytotoxicity and neurotoxicity. Furthermore, in this review, based on mechanistic studies of polystyrene-nanoplastics at the cellular level other than neurons, future directions for overcoming the negative effects of polystyrene-nanoplastics on neurons were suggested.

Studies on the transfer effect of aged polyethylene microplastics in soil-plant system

The widespread use of polyethylene (PE) agricultural films has led to a large accumulation of microplastics in soil, and the environmental effects of microplastics on soil-plants have received increasing attention. In the actual soil environment, microplastics undergo significant changes in their physicochemical properties due to aging, accompanied by complex ecological and environmental effects. However, the quantitative understanding of the environmental effects of microplastic aging in soil-plant systems is still unclear. Therefore, this study investigated the effects of aged and unaged PE microplastics on ecological functions and microplastic transfer mechanisms in soil-plant system, and confirmed the transport behavior of micrometer-sized microplastics (26 μm) within maize plants, expanding the upper size limit of existing studies on microplastic transport within plants. The accumulation of microplastics in maize was also quantitatively assessed in combination with the self-established method of Eu marked PE. The mobility ratio of microplastics from soil to roots, roots to stems, and stems to leaves was 1.07%, 0.76%, and 103.28%, respectively. This study provides a scientific understanding for the environmental effects of microplastics in soil-plants systems quantitatively.

Genome-wide identification and expression analysis of the WNK kinase gene family in soybean

WNK kinases are a unique class of serine/threonine protein kinases that lack a conserved catalytic lysine residue in the kinase domain, hence the name WNK (with no K, i.e., lysine). WNK kinases are involved in various physiological processes in plants, such as circadian rhythm, flowering time, and stress responses. In this study, we identified 26 WNK genes in soybean and analyzed their phylogenetic relationships, gene structures, chromosomal distribution, cis-regulatory elements, expression patterns, and conserved protein motifs. The soybean WNK genes were unevenly distributed on 15 chromosomes and underwent 21 segmental duplication events during evolution. We detected 14 types of cis-regulatory elements in the promoters of the WNK genes, indicating their potential involvement in different signaling pathways. The transcriptome database revealed tissue-specific and salt stress-responsive expression of WNK genes in soybean, the second of which was confirmed by salt treatments and qRT-PCR analysis. We found that most WNK genes were significantly up-regulated by salt stress within 3 h in both roots and leaves, except for WNK5, which showed a distinct expression pattern. Our findings provide valuable insights into the molecular characteristics and evolutionary history of the soybean WNK gene family and lay a foundation for further analysis of WNK gene functions in soybean.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-024-01440-5.

The 3' terminal region of Zika virus RNA contains a conserved G-quadruplex and is unfolded by human DDX17

Zika virus (ZIKV) infection remains a worldwide concern, and currently no effective treatments or vaccines are available. Novel therapeutics are an avenue of interest that could probe viral RNA-human protein communication to stop viral replication. One specific RNA structure, G-quadruplexes (G4s), possess various roles in viruses and all domains of life, including transcription and translation regulation and genome stability, and serves as nucleation points for RNA liquid-liquid phase separation. Previous G4 studies on ZIKV using a quadruplex forming G-rich sequences Mapper located a potential G-quadruplex sequence in the 3' terminal region (TR) and was validated structurally using a 25-mer oligo. It is currently unknown if this structure is conserved and maintained in a large ZIKV RNA transcript and its specific roles in viral replication. Using bioinformatic analysis and biochemical assays, we demonstrate that the ZIKV 3' TR G4 is conserved across all ZIKV isolates and maintains its structure in a 3' TR full-length transcript. We further established the G4 formation using pyridostatin and the BG4 G4-recognizing antibody binding assays. Our study also demonstrates that the human DEAD-box helicases, DDX3X132-607 and DDX17135-555, bind to the 3' TR and that DDX17135-555 unfolds the G4 present in the 3' TR. These findings provide a path forward in potential therapeutic targeting of DDX3X or DDX17's binding to the 3' TR G4 region for novel treatments against ZIKV.

Rapid detection and identification of microplastics from nonchemically treated soil with CARS microspectroscopy

In conventional microplastic (MP) analysis, acid or alkaline digestion is a necessary pretreatment step to remove residual organic matter from environmental samples. However, such a digestion process is not only cumbersome and time-consuming, but also possibly cause severe chemical damage to the MP itself, often making accurate MP characterization difficult. This study demonstrates that broadband coherent anti-Stokes Raman scattering (CARS) microspectroscopy is useful for rapidly detecting and identifying MPs in natural soil without any digestion process. A feasibility test is performed with soil samples, which are known to require the most complicated chemical pretreatment for MP analysis, deliberately mixed with various MP particles. The C-H bond-specific CARS imaging and spectral analysis allow rapid MP particle search and chemical identification even in the presence of other residual particles and strongly fluorescent substances from the soil. It is anticipated that this nondestructive, chemical pretreatment-free CARS approach will be a beneficial tool for studying the ecological impacts of MPs absorbed by terrestrial life, such as plants and soil organisms, as well as for complementary analysis of MPs subject to chemical degradation by digestion in investigating the environmental contamination of the MPs.

Yuanzhi powder facilitated Aβ clearance in APP/PS1 mice: Target to the drainage of glymphatic system and meningeal lymphatic vessels

ETHNOPHARMACOLOGICAL RELEVANCE

Yuanzhi Powder (YZP) is a classical Chinese medicine prescription, which is suitable for the treatment of dementia by "dispelling phlegm and opening orifice". The therapeutic efficacy of YZP on Alzheimer's disease (AD) has been previously reported in our work. However, it remains unclear whether the neuroprotective effect of YZP is linked to β-amyloid(Aβ) clearance through cerebral lymphatic drainage.

AIM OF THE STUDY

The aim was to determine the protective efficacy of YZP against AD and investigate the potential mechanism for eliminating excessive Aβ deposition.

MATERIALS AND METHODS

APP/PS1 mice were divided into four groups of 8 mice each: APP/PS1 group, DONE group, L-YZP group, and H-YZP group. Additionally, 8 wild-type littermates were assigned to the control group (WT group). After 8 weeks of consecutive intragastric administration, behavioral tests, including the open field test, novel object recognition test and Morris Water Maze test, were employed to assess the cognitive abilities of all groups of mice. Nissl staining, immunohistochemistry, and western blotting were utilized to evaluate clearance of excessive Aβ deposition and pathological changes. Furthermore, immunofluorescence was applied to visualize the drainage of the cerebral lymphatic system after fluorescent tracer injection in the cisterna magna.

RESULTS

The administration of YZP significantly attenuated cognitive deficits, cleared excessive Aβ deposition, and improved pathological damage in APP/PS1 mice. Furthermore, YZP effectively enhanced glymphatic system drainage by restoring AQP4 polarization and inhibiting reactive astrogliosis. Additionally, YZP facilitated the drainage of meningeal lymphatic vessels (MLVs) by augmenting their diameter and coverage. Lastly, YZP promoted the elimination of Aβ from the brain to deep cervical lymph nodes.

CONCLUSIONS

The administration of YZP may ameliorate the cognitive deficits and pathological damage in APP/PS1 mice by effectively clearing excessive Aβ deposition. The underlying mechanisms potentially involve Aβ clearance through the cerebral lymphatic system, which includes the glymphatic system and MLVs.

Microplastics induced inflammation in the spleen of developmental Japanese quail (Coturnix japonica) via ROS-mediated p38 MAPK and TNF signaling pathway activation1

Microplastics (MPs) have been found in virtually every environment on earth and become a source of pollution around the world. The toxicology of microplastics on immunity is an emerging area of research, and more studies are needed to fully understand the effects of microplastics exposure on animal health. Therefore, we tried to determine the immunotoxic effects of microplastics on avian spleen by using an animal model- Japanese quail (Coturnix japonica). One-week chicks were exposed to environmentally relevant concentrations of 0.02 mg/kg, 0.4 mg/kg and 8 mg/kg polystyrene microplastics in the feed for 5 weeks. The results demonstrated that microplastics induced microstructural injuries featured by cell disarrangement and vacuolation indicating splenic inflammation. Ultrastructural damages including membrane lysis and mitochondrial vacuolation also suggested inflammatory responses in the spleen by microplastics exposure. Meanwhile, increasing reactive oxygen species (ROS) and Malondialdehyde (MDA) while the inactivation of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) indicated oxidative stress in the spleen. Moreover, the increasing level of proinflammatory cytokines including Tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interleukin-1β (IL-1β), interleukin-6 (IL-6) and decreasing level of anti-inflammatory cytokine interleukin-10 (IL-10) implied splenic inflammation. Furthermore, transcriptomic analysis showed that microplastics induced inflammatory responses in the spleen through p38 mitogen-activated protein kinases (p38 MAPK) pathway activation and tumor necrosis factor (TNF) signaling stimulation. The signaling stimulation also aggravated cell apoptosis in the spleen. The present study may benefit to understand potential mechanisms of developmental immunotoxicology of microplastics.

Dasatinib suppresses collective cell migration through the coordination of focal adhesion and E-cadherin in colon cancer cells

Collective cell migration is an important process in cancer metastasis. Unlike single-cell migration, collective cell migration requires E-cadherin expression in the cell cohort. However, the mechanisms underlying cellular contact and focal adhesions remain unclear. In this study, Src was hypothesized to coordinate focal adhesion and Rab11-mediated E-cadherin distribution during collective cell migration. This study primarily used confocal microscopy to visualize the 3D structure of cell-cell contacts with associated molecules. These results demonstrate that the clinical Src inhibitor dasatinib was less toxic to HT-29 colon cancer cells; instead, the cells aggregated. 3D immunofluorescence imaging showed that Rab11 was localized with E-cadherin at the adherens junctions of the apical cell-cell contacts. In the transwell assay, Rab11 colocalized with a broad range of E-cadherin proteins in collectively migrated cells, and dasatinib treatment significantly suppressed collective cell migration. Transmission electron microscopy demonstrated that dasatinib treatment increased cell membrane protrusion contacts and generated spaces between cells, which may allow epidermal growth factor receptor activity at the cell-cell contacts. This study suggests that dasatinib treatment does not inhibit cell survival but targets Src at different cellular compartments in the coordination of focal adhesions and cell-cell contacts in collective cell migration through E-cadherin dynamics in colon cancer cells.

Emerging Contaminants: An Emerging Risk Factor for Diabetes Mellitus

Emerging contaminants have been increasingly recognized as critical determinants in global public health outcomes. However, the intricate relationship between these contaminants and glucose metabolism remains to be fully elucidated. The paucity of comprehensive clinical data, coupled with the need for in-depth mechanistic investigations, underscores the urgency to decipher the precise molecular and cellular pathways through which these contaminants potentially mediate the initiation and progression of diabetes mellitus. A profound understanding of the epidemiological impact of these emerging contaminants, as well as the elucidation of the underlying mechanistic pathways, is indispensable for the formulation of evidence-based policy and preventive interventions. This review systematically aggregates contemporary findings from epidemiological investigations and delves into the mechanistic correlates that tether exposure to emerging contaminants, including endocrine disruptors, perfluorinated compounds, microplastics, and antibiotics, to glycemic dysregulation. A nuanced exploration is undertaken focusing on potential dietary sources and the consequential role of the gut microbiome in their toxic effects. This review endeavors to provide a foundational reference for future investigations into the complex interplay between emerging contaminants and diabetes mellitus.

Current perspectives, challenges, and future directions in the electrochemical detection of microplastics

Microplastics (5 μm) are a developing threat that contaminate every environmental compartment. The detection of these contaminants is undoubtedly an important topic of study because of their high potential to cause harm to ecosystems. For many years, scientists have been assiduously striving to surmount the obstacle of detection restrictions and minimize the likelihood of receiving results that are either false positives or false negatives. This study covers the current state of electrochemical sensing technology as well as its application as a low-cost analytical platform for the detection and characterization of novel contaminants. Examples of detection mechanisms, electrode modification procedures, device configuration, and performance are given to show how successful these approaches are for monitoring microplastics in the environment. Additionally included are the recent developments in nanoimpact techniques. Compared to electrochemical methods for microplastic remediation, the use of electrochemical sensors for microplastic detection has received very little attention. With an overview of microplastic electrochemical sensors, this review emphasizes the promise of existing electrochemical remediation platforms toward sensor design and development. In order to enhance the monitoring of these substances, a critical assessment of the requirements for future research, challenges associated with detection, and opportunities is provided. In addition to-or instead of-the now-in-use laboratory-based analytical equipment, these technologies can be utilized to support extensive research and manage issues pertaining to microplastics in the environment and other matrices.

Transmission-selective muscle pathology induced by the active propagation of mutant huntingtin across the human neuromuscular synapse

Neuron-to-neuron transmission of aggregation-prone, misfolded proteins may potentially explain the spatiotemporal accumulation of pathological lesions in the brains of patients with neurodegenerative protein-misfolding diseases (PMDs). However, little is known about protein transmission from the central nervous system to the periphery, or how this propagation contributes to PMD pathology. To deepen our understanding of these processes, we established two functional neuromuscular systems derived from human iPSCs. One was suitable for long-term high-throughput live-cell imaging and the other was adapted to a microfluidic system assuring that connectivity between motor neurons and muscle cells was restricted to the neuromuscular junction. We show that the Huntington's disease (HD)-associated mutant HTT exon 1 protein (mHTTEx1) is transmitted from neurons to muscle cells across the human neuromuscular junction. We found that transmission is an active and dynamic process that starts before aggregate formation and is regulated by synaptic activity. We further found that transmitted mHTTEx1 causes HD-relevant pathology at both molecular and functional levels in human muscle cells, even in the presence of the ubiquitous expression of mHTTEx1. In conclusion, we have uncovered a causal link between mHTTEx1 synaptic transmission and HD pathology, highlighting the therapeutic potential of blocking toxic protein transmission in PMDs.