Polystyrene microplastic particles induce autophagic cell death in BEAS-2B human bronchial epithelial cells

Integration of transcriptomics and metabolomics reveal cytotoxic mechanisms of Polyethylene terephthalate microplastics in BEAS-2B cells

Polyethylene terephthalate microplastics (PET-MPs) have emerged as significant environmental pollutants with potential health risks. This study investigates the cytotoxic effects of PET-MPs on BEAS-2B lung epithelial cells through integrated transcriptomic and metabolomic analyses. The results of the CCK8 assay showed a reduction in the viability of BEAS-2B cells following continuous exposure to PET-MPs. Transcriptomic analysis identified 1412 differentially expressed genes (DEGs) mainly enriched in apoptosis and extracellular matrix organization processes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these DEGs are predominantly involved in the PI3K-Akt, TNF, and MAPK signaling pathways. Metabolomic analysis identified 2869 differentially expressed metabolites (DEMs), mainly associated with pyrimidine, arginine, proline, and β-alanine metabolism pathways. Multi-omics analysis indicated that PET-MPs primarily disrupt lipid metabolism, which may lead to an increased risk of apoptosis. We hypothesize that PET-MPs affect lipid metabolism by up-regulating the ANGPTL4 gene, thereby promoting cellular apoptosis. This study reveals the mechanisms of PET-MPs toxicity, emphasizing the potential risks they pose to human health.

Co-exposure to polyethylene microplastics and house dust mites aggravates airway epithelial barrier dysfunction and airway inflammation via CXCL1 signaling pathway in a mouse model

BACKGROUND

Environmental pollutants have been found to contribute to the development and acute exacerbation of asthma. Microplastics (MPs) have received widespread attention as an emerging global pollutant. Airborne MPs can cause various adverse health effects. Due to their hydrophobicity, MPs can act as a carrier for other pollutants, pathogens, and allergens. This carrier effect of MPs may adsorb allergens and thus make the body exposed to MPs and a large number of allergens simultaneously. We hypothesized that co-exposure to inhaled MPs and aeroallergens may promote the development of airway inflammation of asthma by disrupting the airway epithelial barrier.

METHODS

The effects of co-exposure to Polyethylene microplastics (PE-MPs) and allergens on allergic airway inflammation and airway epithelial barrier were examined in a mouse model of asthma. The mice were divided into four groups: (i) Control group, treated only with PBS; (ii) MP group, exposed to PE-MPs and PBS; (iii) HDM group, mice were sensitized and challenged with HDM, and intranasally treated with PBS; (iv) HDM + MP group, mice were sensitized and challenged with HDM, and intranasally treated with PE-MPs. Histology and ELISA assays were used to evaluate the severity of airway inflammation. FITC-dextran permeability assay, immunofluorescence assay, and RT-PCR were used to evaluate the airway epithelial barrier function and the expression of relevant molecules. Transcriptomics analysis with lung tissue sequencing was conducted to identify possible pathways responsible for the effects of PE-MPs.

RESULTS

Co-exposure of mice to PE-MPs and HDM induced a higher degree of inflammatory cell infiltration, bronchial goblet cell hyperplasia, collagen deposition, allergen sensitization, and Th2 immune bias than exposure to HDM alone. Co-exposure to PE-MPs and HDM aggravated oxidative stress injury in the lung and the production of cytokine IL-33 in the BALF. In addition, co-exposure of mice to PE-MPs and HDM resulted in a more pronounced decrease in the expression of relevant molecules of the airway epithelial barrier and more significant increase in the permeability of airway epithelia. Lung tissue transcriptomics analysis revealed that PE-MPs exposure was associated with CXCL1 signaling and neutrophil activation.

CONCLUSION

Co-exposure to MPs and HDM may promote airway inflammation and airway epithelial barrier disruption and induce immune responses characterized by CXCL1 signaling and neutrophilic inflammation.

Airborne micro- and nanoplastics: emerging causes of respiratory diseases

Airborne micro- and nanoplastics (AMNPs) are ubiquitously present in human living environments and pose significant threats to respiratory health. Currently, much research has been conducted on the relationship between micro- and nanoplastics (MNPs) and cardiovascular and gastrointestinal diseases, yet there is a clear lack of understanding regarding the link between AMNPs and respiratory diseases. Therefore, it is imperative to explore the relationship between the two. Recent extensive studies by numerous scholars on the characteristics of AMNPs and their relationship with respiratory diseases have robustly demonstrated that AMNPs from various sources significantly influence the onset and progression of respiratory conditions. Thus, investigating the intrinsic mechanisms involved and finding necessary preventive and therapeutic measures are crucial. In this review, we primarily describe the fundamental characteristics of AMNPs, their impact on the respiratory system, and the intrinsic toxic mechanisms that facilitate disease development. It is hoped that this article will provide new insights for further research and contribute to the advancement of human health.

Recent advances on transport and transformation mechanism of nanoplastics in lung cells

Microplastics (MPs) are solid plastic particles less than or equal to 5 mm in size that are insoluble in water, and when the diameter is further reduced to <1 micrometer (μm), we call them nanoplastics (NPs). MPs and NPs are widely present in the atmosphere, and plastic particles have also been detected in the sputum of patients with respiratory diseases. This warns us that these tiny plastic particles are a potential threat to human respiratory health. The lungs, as the main organs of the respiratory system, are more likely to be adversely affected by inhaled NPs. However, the mechanism of transport and transformation of NPs in the lung is not clear, so our review mainly focuses on a series of effects and mechanisms of NPs on lung cells through absorption, distribution, metabolism, excretion (ADME) after inhalation into the human body. The most commonly used models in these experimental studies we focus on are A549 and BEAS-2B cells, which are used to model the lung cell response to plastic particles. In addition, we also summarize some shortcomings of these experiments and prospects for future studies, hoping to provide further clues for future studies and contribute to the prevention of related hazards and diseases.

Microplastics in indoor and outdoor environments in China: Characteristic and human exposure risk assessment

Human exposure to microplastics (MPs) has led to global health concerns, but our knowledge of the characteristics and human exposure of airborne MPs is limited. Adults may have different exposure patterns and lifestyles from other age groups. Therefore, this study aims to determine the MPs exposure among adults at various locations and during different time periods. MPs were collected and detected through passive sampling and laser direct infrared (LDIR) imaging (Agilent 8700) at five locations including: dormitory, dining hall, office, library, and outdoor; the sampling lasted for 3 months. The highest concentration of indoor MPs was detected in the dining hall (193 ± 8 MPs/m2/day), whereas the lowest was detected in the library (113 ± 4 MPs/m2/day). Among all sampling points, the outdoor locations had the lowest MPs concentrations (92 ± 4 MPs/m2/day). The length of the MPs ranged from 10 μm－760 μm. Pellets (54.6 %), fibres (21.6 %), and fragments (23.8 %) were the shapes identified in this research. Polyamide (51.7 %) was the most prevalent polymer type at all sampling points. This article conducted respiratory exposure assessments of MPs for males and females of different ages (age ranges: 18－21; 21－30; 31－40; 41－60) in different environments and at different times. For both weekends and weekdays, dormitories contributed the most to MPs respiratory exposure. Males aged 31－40 years had the highest exposure with an average of 266 particles/day, whereas females aged 18－21 (157 particles/day) had the lowest exposure. Differences in respiratory rate according to age and gender may be the main reason for these results. These findings indicate that further research into the adult MPs inhalation exposure under indoor and outdoor conditions is crucial.

Molecular and Cellular Effects of Microplastics and Nanoplastics: Focus on Inflammation and Senescence

Microplastics and nanoplastics (MNPs) are ubiquitous environmental contaminants. Their prevalence, persistence, and increasing industrial production have led to questions about their long-term impact on human and animal health. This narrative review describes the effects of MNPs on oxidative stress, inflammation, and aging. Exposure to MNPs leads to increased production of reactive oxygen species (ROS) across multiple experimental models, including cell lines, organoids, and animal systems. ROS can cause damage to cellular macromolecules such as DNA, proteins, and lipids. Direct interaction between MNPs and immune cells or an indirect result of oxidative stress-mediated cellular damage may lead to increased production of pro-inflammatory cytokines throughout different MNP-exposure conditions. This inflammatory response is a common feature in the pathogenesis of neurodegenerative, cardiovascular, and other age-related diseases. MNPs also act as cell senescence inducers by promoting mitochondrial dysfunction, impairing autophagy, and activating DNA damage responses, exacerbating cellular aging altogether. Increased senescence of reproductive cells and transfer of MNPs/induced damages from parents to offspring in animals further corroborates the transgenerational health risks of the tiny particles. This review aims to provoke a deeper investigation into the notorious effects these pervasive particles may have on human well-being and longevity.

A review on advancements in atmospheric microplastics research: The pivotal role of machine learning

Microplastics (MPs), recognized as emerging pollutants, pose significant potential impacts on the environment and human health. The investigation into atmospheric MPs is nascent due to the absence of effective characterization methods, leaving their concentration, distribution, sources, and impacts on human health largely undefined with evidence still emerging. This review compiles the latest literature on the sources, distribution, environmental behaviors, and toxicological effects of atmospheric MPs. It delves into the methodologies for source identification, distribution patterns, and the contemporary approaches to assess the toxicological effects of atmospheric MPs. Significantly, this review emphasizes the role of Machine Learning (ML) and Artificial Intelligence (AI) technologies as novel and promising tools in enhancing the precision and depth of research into atmospheric MPs, including but not limited to the spatiotemporal dynamics, source apportionment, and potential health impacts of atmospheric MPs. The integration of these advanced technologies facilitates a more nuanced understanding of MPs' behavior and effects, marking a pivotal advancement in the field. This review aims to deliver an in-depth view of atmospheric MPs, enhancing knowledge and awareness of their environmental and human health impacts. It calls upon scholars to focus on the research of atmospheric MPs based on new technologies of ML and AI, improving the database as well as offering fresh perspectives on this critical issue.

Long-term polystyrene nanoparticles exposure reduces electroretinal responses and exacerbates retinal degeneration induced by light exposure

The impact of plastic pollution on living organisms have gained significant research attention. However, the effects of nanoplastics (NPs) on retina remain unclear. This study aimed to investigate the effect of long-term polystyrene nanoparticles (PS-NPs) exposure on mouse retina. Eight weeks old C57BL/6 J mice were exposed to PS-NPs at the diameter of 100 nm and concentration of 10 mg/L in drinking water for 3 months. PS-NPs were able to penetrate the blood-retina barrier, accumulated at retinal tissue, caused increased oxidative stress level and reduced scotopic electroretinal responses without remarkable structural damage. PS-NPs exposure caused cytotoxicity and reactive oxygen species accumulation in cultured photoreceptor cell. PS-NPs exposure increased oxidative stress level in retinal pigment epithelial (RPE) cells, leading to changes of gene and protein expression indicative of compromised phagocytic activity and cell junction formation. Long-term PS-NPs exposure also aggravated light-induced photoreceptor cell degeneration and retinal inflammation. The transcriptomic profile of PS-NPs-exposed, light-challenged retinal tissue shared similar features with those of age-related macular degeneration (AMD) patients in the activation of complement-mediated phagocytic and proinflammatory responses. Collectively, these findings demonstrated the oxidative stress- and inflammation-mediated detrimental effect of PS-NPs on retinal function, suggested that long-term PS-NPs exposure could be an environmental risk factor contributing to retinal degeneration.

Research Progress on Micro(nano)plastic-Induced Programmed Cell Death Associated with Disease Risks

Due to their robust migration capabilities, slow degradation, and propensity for adsorbing environmental pollutants, micro(nano)plastics (MNPs) are pervasive across diverse ecosystems. They infiltrate various organisms within different food chains through multiple pathways including inhalation and dermal contact, and pose a significant environmental challenge in the 21st century. Research indicates that MNPs pose health threats to a broad range of organisms, including humans. Currently, extensive detection data and studies using experimental animals and in vitro cell culture indicate that MNPs can trigger various forms of programmed cell death (PCD) and can induce various diseases. This review provides a comprehensive and systematic analysis of different MNP-induced PCD processes, including pyroptosis, ferroptosis, autophagy, necroptosis, and apoptosis, based on recent research findings and focuses on elucidating the links between PCD and diseases. Additionally, targeted therapeutic interventions for these diseases are described. This review provides original insights into the opportunities and challenges posed by current research findings. This review evaluates ways to mitigate various diseases resulting from cell death patterns. Moreover, this paper enhances the understanding of the biohazards associated with MNPs by providing a systematic reference for subsequent toxicological research and health risk mitigation efforts.

Realistic Nanoplastics Induced Pulmonary Damage via the Crosstalk of Ferritinophagy and Mitochondrial Dysfunction

The smaller size fraction of plastics may be more substantially existing and detrimental than larger-sized particles. However, reports on nanoplastics (NPs), especially their airborne occurrences and potential health hazards to the respiratory system, are scarce. Previous studies limit the understanding of their real respiratory effects, since sphere-type polystyrene (PS) nanoparticles differ from NPs occurring in nature with respect to their physicochemical properties. Here, we employ a mechanical breakdown method, producing NPs directly from bulk plastic, preserving NP properties in nature. We report that among four relatively high abundance NP materials PS, polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polyethylene (PE) with a size of 100 nm, PVC induced slightly more severe lung toxicity profiles compared to the other plastics. The lung cytotoxicity of NPs is higher than that of commercial PS NPs and comparable to natural particles silicon dioxide (SiO2) and anatase titanium dioxide (TiO2). Mechanistically, BH3-interacting domain death agonist (Bid) transactivation-mediated mitochondrial dysfunction and nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy or ferroptosis are likely common mechanisms of NPs regardless of their chemical composition. This study provides relatively comprehensive data for evaluating the risk of atmospheric NPs to lung health.

Transforming pollution into solutions: A bibliometric analysis and sustainable strategies for reducing indoor microplastics while converting to value-added products

Microplastics (MPs), as emerging indoor contaminants, have garnered attention due to their ubiquity and unresolved implications for human health. These tiny particles have permeated indoor air and water, leading to inevitable human exposure. Preliminary evidence suggests MP exposure could be linked to respiratory, gastrointestinal, and potentially other health issues, yet the full scope of their effects remains unclear. To map the overall landscape of this research field, a bibliometric analysis based on research articles retrieved from the Web of Science database was conducted. The study synthesizes the current state of knowledge and spotlights the innovative mitigation strategies proposed to curb indoor MP pollution. These strategies involve minimizing the MP emission from source, advancements in filtration technology, aimed at reducing the MP exposure. Furthermore, this research sheds light on cutting-edge methods for converting MP waste into value-added products. These innovative approaches not only promise to alleviate environmental burdens but also contribute to a more sustainable and circular economy by transforming waste into resources such as biofuels, construction materials, and batteries. Despite these strides, this study acknowledges the ongoing challenges, including the need for more efficient removal technologies and a deeper understanding of MPs' health impacts. Looking forward, the study underscores the necessity for further research to fill these knowledge gaps, particularly in the areas of long-term health outcomes and the development of standardized, reliable methodologies for MP detection and quantification in indoor settings. This comprehensive approach paves the way for future exploration and the development of robust solutions to the complex issue of microplastic pollution.

Micro-and nano-plastics induce kidney damage and suppression of innate immune function in zebrafish (Danio rerio) larvae

Aquatic environments serve as critical repositories for pollutants and have significantly accumulated micro- and nanoplastics (MNPs) due to the extensive production and application of plastic products. While the disease resistance and immunity of fish are closely linked to the condition of their aquatic habitats, the specific effects of nanoplastics (NPs) and microplastics (MPs) within these environments on fish immune functions are still not fully understood. The present study utilized zebrafish (Danio rerio) embryos and larvae as model organisms to examine the impacts of polystyrene NPs (100 nm) and MPs (5 μm) on fish immune responses. Our findings reveal that NPs and MPs tend to accumulate on the surfaces of embryos and within the intestines of larvae, triggering oxidative stress and significantly increasing susceptibility to Edwardsiella piscicida infection in zebrafish larvae. Transmission electron microscopy examined that both NPs and MPs inflicted damage to the kidney, an essential immune organ, with NPs predominantly inducing endoplasmic reticulum stress and MPs causing lipid accumulation. Transcriptomic analysis further demonstrated that both NPs and MPs significantly suppress the expression of key innate immune pathways, notably the C-type lectin receptor signaling pathway and the cytosolic DNA-sensing pathway. Within these pathways, the immune factor interleukin-1 beta (il1b) was consistently downregulated in both exposure groups. Furthermore, exposure to E. piscicida resulted in restricted upregulation of il1b mRNA and protein levels, likely contributing to diminished disease resistance in zebrafish larvae exposed to MNPs. Our findings suggest that NPs and MPs similarly impair the innate immune function of zebrafish larvae and weaken their disease resistance, highlighting the significant environmental threat posed by these pollutants.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.

Probabilistic Estimation of Airborne Micro- and Nanoplastic Intake in Humans

Little research exists on the magnitude, variability, and uncertainty of human exposure to airborne micro- and nanoplastics (AMNPs), despite their critical role in human exposure to MNPs. We probabilistically estimate the global intake of AMNPs through three main pathways: indoor inhalation, outdoor inhalation, and ingestion during indoor meals, for both children and adults. The median inhalation of AMPs is 1,207.7 (90% CI, 42.5-8.48 × 104) and 1,354.7 (90% CI, 47.4-9.55 × 104) N/capita/day for children and adults, respectively. The annual intake of AMPs is 13.18 mg/capita/a for children and 19.10 mg/capita/a for adults, which is approximately one-fifth and one-third of the mass of a standard stamp, assuming a consistent daily intake of medians. The majority of AMP number intake occurs through inhalation, while the ingestion of deposited AMPs during meals contributes the most in terms of mass. Furthermore, the median ANP intake through outdoor inhalation is 9,638.1 N/day (8.23 × 10-6 μg/d) and 5,410.6 N/day (4.62 × 10-6 μg/d) for children and adults, respectively, compared to 5.30 × 105 N/day (5.79 × 10-4 μg/d) and 6.00 × 105 N/day (6.55 × 10-4 μg/d) via indoor inhalation. Considering the increased toxicity of smaller MNPs, the significant number of ANPs inhaled warrants great attention. Collaborative efforts are imperative to further elucidate and combat the current MPN risks.

Sonicated polyethylene terephthalate nano- and micro-plastic-induced inflammation, oxidative stress, and autophagy in vitro

The environmental presence of nano- and micro-plastic particles (NMPs) is suspected to have a negative impact on human health. Environmental NMPs are difficult to sample and use in life science research, while commercially available plastic particles are too morphologically uniform. Additionally, this NMPs exposure exhibited biological effects, including cell internalization, oxidative stress, inflammation, cellular adaptation, and genotoxicity. Therefore, developing new methods for producing heterogenous NMPs as observed in the environment is important as reference materials for research. Thus, we aimed to generate and characterize NMPs suspensions using a modified ultrasonic protocol and to investigate their biological effects after exposure to different human cell lines. To this end, we produced polyethylene terephthalate (PET) NMPs suspensions and characterized the particles by dynamic light scattering and scanning electron microscopy. Ultrasound treatment induced polymer degradation into smaller and heterogeneous PET NMPs shape fragments with similar surface chemistry before and after treatment. A polydisperse suspension of PET NMPs with 781 nm in average size and negative surface charge was generated. Then, the PET NMPs were cultured with two human cell lines, A549 (lung) and HaCaT (skin), addressing inhalation and topical exposure routes. Both cell lines interacted with and have taken up PET NMPs as quantified via cellular granularity assay. A549 but not HaCaT cell metabolism, viability, and cell death were affected by PET NMPs. In HaCaT keratinocytes, large PET NMPs provoked genotoxic effects. In both cell lines, PET NMPs exposure affected oxidative stress, cytokine release, and cell morphology, independently of concentration, which we could relate mechanistically to Nrf2 and autophagy activation. Collectively, we present a new PET NMP generation model suitable for studying the environmental and biological consequences of exposure to this polymer.

Important Factors Affecting Induction of Cell Death, Oxidative Stress and DNA Damage by Nano- and Microplastic Particles In Vitro

We have described the influence of selected factors that increase the toxicity of nanoplastics (NPs) and microplastics (MPs) with regard to cell viability, various types of cell death, reactive oxygen species (ROS) induction, and genotoxicity. These factors include plastic particle size (NPs/MPs), zeta potential, exposure time, concentration, functionalization, and the influence of environmental factors and cell type. Studies have unequivocally shown that smaller plastic particles are more cytotoxic, penetrate cells more easily, increase ROS formation, and induce oxidative damage to proteins, lipids, and DNA. The toxic effects also increase with concentration and incubation time. NPs with positive zeta potential are also more toxic than those with a negative zeta potential because the cells are negatively charged, inducing stronger interactions. The deleterious effects of NPs and MPs are increased by functionalization with anionic or carboxyl groups, due to greater interaction with cell membrane components. Cationic NPs/MPs are particularly toxic due to their greater cellular uptake and/or their effects on cells and lysosomal membranes. The effects of polystyrene (PS) vary from one cell type to another, and normal cells are more sensitive to NPs than cancerous ones. The toxicity of NPs/MPs can be enhanced by environmental factors, including UV radiation, as they cause the particles to shrink and change their shape, which is a particularly important consideration when working with environmentally-changed NPs/MPs. In summary, the cytotoxicity, oxidative properties, and genotoxicity of plastic particles depends on their concentration, duration of action, and cell type. Also, NPs/MPs with a smaller diameter and positive zeta potential, and those exposed to UV and functionalized with amino groups, demonstrate higher toxicity than larger, non-functionalized and environmentally-unchanged particles with a negative zeta potential.

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.

Inhalation exposure to polystyrene nanoplastics induces chronic obstructive pulmonary disease-like lung injury in mice through multi-dimensional assessment

Nanoplastics are widely distributed in indoor and outdoor air and can be easily inhaled into human lungs. However, limited studies have investigated the impact of nanoplastics on inhalation toxicities, especially on the initiation and progression of chronic obstructive pulmonary disease (COPD). To fill the gap, the present study used oronasal aspiration to develop mice models. Mice were exposed to polystyrene nanoplastics (PS-NPs) at three concentrations, as well as the corresponding controls, for acute, subacute, and subchronic exposure. As a result, PS-NPs could accumulate in exposed mice lungs and influence lung organ coefficient. Besides, PS-NPs induced local and systemic oxidative stress, inflammation, and protease-antiprotease imbalance, resulting in decreased respiratory function and COPD-like lesions. Meanwhile, PS-NPs could trigger the subcellular mechanism to promote COPD development by causing mitochondrial dysfunctions and endoplasmic reticulum (ER) stress. Mechanistically, ferroptosis played an important role in the COPD-like lung injury induced by PS-NPs. In summary, the present study comprehensively and systematically indicates that PS-NPs can damage human respiratory health and increase the risk for COPD.

Microplastic and plastic pollution: impact on respiratory disease and health

Throughout their lifecycle, from production to use and upon disposal, plastics release chemicals and particles known as micro- and nanoplastics (MNPs) that can accumulate in the environment. MNPs have been detected in different locations of the human body, including in our lungs. This is likely a consequence of MNP exposure through the air we breathe. Yet, we still lack a comprehensive understanding of the impact that MNP exposure may have on respiratory disease and health. In this review, we have collated the current body of evidence on the implications of MNP inhalation on human lung health from in vitro, in vivo and occupational exposure studies. We focused on interactions between MNP pollution and different specific lung-resident cells and respiratory diseases. We conclude that it is evident that MNPs possess the capacity to affect lung tissue in disease and health. Yet, it remains unclear to which extent this occurs upon exposure to ambient levels of MNPs, emphasising the need for a more comprehensive evaluation of environmental MNP exposure levels in everyday life.

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.

Endoplasmic reticulum stress exacerbates microplastics-induced toxicity in animal cells

Human and animal exposure to microplastics (MPs) contained in food is inevitable because of their widespread existence in the environment. Nevertheless, MPs toxicity studies in ruminants often lack attention. Here, we assessed the cytotoxicity of polystyrene microplastics (PS MPs) on goat mammary epithelial cells (GMECs). Compared to controls, PS MPs treatment significantly reduced cell viability, altered cell morphology and disrupted organelle integrity. Detection of membrane potential and reactive oxygen species (ROS) suggested that PS MPs induced mitochondrial dysfunction and oxidative stress. Further transcriptome analysis also confirmed alterations in these pathways. In addition, several genes related to endoplasmic reticulum (ER) homeostasis were significantly regulated in the transcriptional profile. Subsequent experiments confirmed that PS MPs induce ER stress via the PERK/eIF2α/CHOP pathway, accompanied by intracellular Ca2+ overload. Meanwhile, downstream activation of the Bax/Bcl-2 pathway and caspase cascade released apoptotic signals, which led to apoptosis in GMECs. Interestingly, the addition of PERK inhibitor (ISRIB) attenuated PS MPs-induced ER stress and apoptosis, which suggests that ER stress may exacerbate PS MPs-induced cytotoxicity. This work reveals the impact of MPs on mammalian cytotoxicity, enriches the mechanisms for the toxicity of MPs, and provides insight for further assessment of the risk of MPs in food.

Airborne microplastics: A narrative review of potential effects on the human respiratory system

There has been growing evidence showing the widespread of airborne microplastics (AMPs) in many regions of the world, raising concerns about their impact on human health. This review aimed to consolidate recent literature on AMPs regarding their physical and chemical characteristics, deposition in the human respiratory tract, translocation, occurrence from human studies, and toxic effects determined in vitro and in vivo. The physical characteristics influence interactions with cell membranes, cellular internalization, accumulation, and cytotoxicity resulting from cell membrane damage and oxidative stress. In addition, prolonged exposure to AMP-associated toxic chemicals might lead to significant health effects. Most toxicological assessments of AMPs in vitro and in vivo have demonstrated that oxidative stress and inflammation are major mechanisms of action for their toxic effects. Elevated reactive oxygen species production could lead to mitochondrial dysfunction, inflammatory responses, and subsequent apoptosis in experimental models. To date, there has been some evidence suggesting exposure in humans. However, the data are still insufficient, and adverse human health effects need to be investigated. Future research on the existence, exposure, and health effects of AMPs is required for developing preventive and mitigation measures to protect human health.

Recent progress of microplastic toxicity on human exposure base on in vitro and in vivo studies

Microplastics are widely distributed in the environment, including the atmosphere, soil and water bodies. They have been found to have toxic effects on organisms. The impact on human health is also receiving considerable attention. Microplastics can be found in drinking water, food, air and plastic products, and they can enter human body through the pathways such as ingestion, inhalation, and skin contact. After exposure to microplastics, they can induce cellular toxicity and produce toxic effects on multiple organs and systems, including the digestive, respiratory, nervous, reproductive and cardiovascular systems. This paper presents a comprehensive review and analysis on the recent progress of human exposure studies, in vitro experiments, rodent experiments, and other model experiments in microplastic human toxicity research. It comprehensively analyzes the potential human toxic effects of microplastics, providing a theoretical basis for further research on microplastic human toxicity and its mechanisms. Furthermore, this paper highlights the knowledge gaps and provides the recommendations for future research on human toxicity of microplastics.

miRNA transcriptomics analysis shows miR-483-5p and miR-503-5p targeted miRNA in extracellular vesicles from severe acute pancreatitis-associated lung injury patients

AIM

This study sought to identify potential biomarkers and miRNA-mRNA networks within extracellular vesicles (EVs) for detecting severe acute pancreatitis-associated lung injury (SAPALI).

METHODS

Blood-derived EVs were isolated, and their miRNA transcriptomic profiles were comprehensively analyzed using miRBase v.21 database along with miRDeep2 tool to predict novel miRNAs. DEGseq R package was deployed for the identification of differentially expressed miRNAs (DEMs). Protein-protein interaction (PPI) networks were assembled using STRING and Cytoscape. A lung injury model was established using Lipopolysaccharide (LPS)-induced BEAS-2B cells, chosen for their respiratory epithelial origin and pertinent association with lung injury. The expression levels of targeted miRNA and associated proteins, TLR4, NF-κB mRNA were quantified via RT-PCR and Western Blot. Levels of IL-6, IL-1β, TNF-α, and ROS were measured using designated kits. Dual-luciferase reporter assay was conducted to examine the interaction between miRNA and proteins.

RESULTS

The comparisons between the SAPALI and the control group revealed 10 DEM, including miR-503-5p and miR-483-5p. The cytoHubba plugin in Cytoscape identified three principal miRNA-mRNA interactions: miR-483-5p with PTK2 and HDAC2; miR-28-5p with MAPK1, TP53BP1, SEMA3A; and miR-503-5p with PPP1CB, SEMA6D, EPHB2, UNC5B. The SAPALI model exhibited elevated miR-503-5p, HDAC2 and inflammatory markers, with a decline UNC5B, miR-483-5p and miR-28-5p. Transfection with miR-503-5p and miR-483-5p inhibitors increased the levels of their supposed binding proteins but not miR-28-5p inhibitor. The Dual-luciferase reporter gene assay identified the interaction of miR-503-5p with UNC5B, and miR-483-5p with HDAC2, but not miR-28-5p with TP53BP1.

CONCLUSIONS

Our study maps miRNA-mRNA interactions in SAPALI, identifying miR-503-5p and miR-483-5p as critical regulatory miRNAs.

Human biomonitoring of microplastics and health implications: A review

BACKGROUND

Microplastics (MPs) are plastic particles (<5 mm) ubiquitous in water, soil, and air, indicating that humans can be exposed to MPs through ingestion of water and food, and inhalation.

OBJECTIVE

This review provides an overview of the current human biomonitoring data available to evaluate human exposure and health impact of MPs.

METHOD

We compiled 91 relevant studies on MPs in human matrices and MPs toxicological endpoints to provide evidence on MPs distribution in the different tissues and the implications this can have from a health perspective.

RESULTS

Human exposure to MPs has been corroborated by the detection of MPs in different human biological samples including blood, urine, stool, lung tissue, breast milk, semen and placenta. Although humans have clearance mechanisms protecting them from potentially harmful substances, health risks associated to MPs exposure include the onset of inflammation, oxidative stress, and DNA damage, potentially leading to cardiovascular and respiratory diseases, as well as cancer, as suggested by in vitro and in vivo studies.

CONCLUSION

Based on compiled data, MPs have been recurrently identified in different human tissues and fluids, suggesting that humans are exposed to MPs through inhalation and ingestion. Despite differences in MPs concentrations appear in exposed and non-exposed people, accumulation and distribution pathways and potential human health hazards is still at an infant stage. Human biomonitoring data enables the assessment of human exposure to MPs and associated risks, and this information can contribute to draw management actions and guidelines to minimize MP release to the environment, and thus, reduce human uptake.

Biomarkers of oxidative stress, inflammation, and genotoxicity to assess exposure to micro- and nanoplastics. A literature review

The increased awareness about possible health effects arising from micro- and nanoplastics (MNPs) pollution is driving a huge amount of studies. Many international efforts are in place to better understand and characterize the hazard of MNPs present in the environment. The literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology in two different databases (PubMed and Embase). The selection of articles was carried out blind, screening titles and abstracts according to inclusion and exclusion criteria. In general, these studies rely on the methodology already in use for assessing hazard from nanomaterials and particles of concern. However, only a limited number of studies have so far directly measured human exposure to MNPs and examined the relationship between such exposure and its impact on human health. This review aims to provide an overview of the current state of research on biomarkers of oxidative stress, inflammation, and genotoxicity that have been explored in relation to MNPs exposure, using human, cellular, animal, and plant models. Both in-vitro and in-vivo models suggest an increased level of oxidative stress and inflammation as the main mechanism of action (MOA) leading to adverse effects such as chronic inflammation, immunotoxicity and genotoxicity. With the identification of such biological endpoints, representing critical key initiating events (KIEs) towards adaptive or adverse outcomes, it is possible to identify a panel of surrogate biomarkers to be applied and validated especially in occupational settings, where higher levels of exposure may occur.

Crizotinib induces pulmonary toxicity by blocking autophagy flux in alveolar epithelial cells

Crizotinib is the first-line drug for advanced non-small cell lung cancer with the abnormal expression of anaplastic lymphoma kinase gene. Severe, life-threatening, or fatal interstitial lung disease/pneumonia has been reported in patients treated with crizotinib. The clinical benefit of crizotinib is limited by its pulmonary toxicity, but the underlying mechanisms have not been adequately studied, and protective strategies are relatively scarce. Here, we established an in vivo mouse model in which crizotinib was continuously administered to C57BL/6 at 100 mg/kg/day for 6 weeks and verified that crizotinib induced interstitial lung disease in vivo, which was consistent with the clinical observations. We further treated BEAS-2B and TC-1 cells, the alveolar epithelial cell lines, with crizotinib and found the increased apoptosis rate. We proved that crizotinib-blocked autophagic flux caused apoptosis of the alveolar epithelial cells and then promoted the recruitment of immune cells, suggesting that limited autophagy activity was the key reason for pulmonary injury and inflammation caused by crizotinib. Subsequently, we found that metformin could reduce the macrophage recruitment and pulmonary fibrosis by recovering the autophagy flux, thereby ameliorating impaired lung function caused by crizotinib. In conclusion, our study revealed the mechanism of crizotinib-induced apoptosis of alveolar epithelial cells and activation of inflammation during the onset of pulmonary toxicity and provided a promising therapeutic strategy for the treatment of crizotinib-induced pulmonary toxicity.

The Effect of Plastic-Related Compounds on Transcriptome-Wide Gene Expression on CYP2C19-Overexpressing HepG2 Cells

In recent years, plastic and especially microplastic in the oceans have caused huge problems to marine flora and fauna. Recently, such particles have also been detected in blood, breast milk, and placenta, underlining their ability to enter the human body, presumably via the food chain and other yet-unknown mechanisms. In addition, plastic contains plasticizers, antioxidants, or lubricants, whose impact on human health is also under investigation. At the cellular level, the most important enzymes involved in the metabolism of xenobiotic compounds are the cytochrome P450 monooxygenases (CYPs). Despite their extensive characterization in the maintenance of cellular balance, their interactions with plastic and related products are unexplored. In this study, the possible interactions between several plastic-related compounds and one of the most important cytochromes, CYP2C19, were analyzed. By applying virtual compound screening and molecular docking to more than 1000 commercially available plastic-related compounds, we identified candidates that are likely to interact with this protein. A growth inhibition assay confirmed their cytotoxic activity on a CYP2C19-transfected hepatic cell line. Subsequently, we studied the effect of the selected compounds on the transcriptome-wide gene expression level by conducting RNA sequencing. Three candidate molecules were identified, i.e., 2,2'-methylene bis(6-tert-butyl-4-methylphenol), 1,1-bis(3,5-di-tert-butyl-2-hydroxyphenyl) ethane, and 2,2'-methylene bis(6-cyclohexyl-4-methylphenol)), which bound with a high affinity to CYP2C19 in silico. They exerted a profound cytotoxicity in vitro and interacted with several metabolic pathways, of which the 'cholesterol biosynthesis process' was the most affected. In addition, other affected pathways involved mitosis, DNA replication, and inflammation, suggesting an increase in hepatotoxicity. These results indicate that plastic-related compounds could damage the liver by affecting several molecular pathways.

Photodegradation of Microplastics by ZnO Nanoparticles with Resulting Cellular and Subcellular Responses

Both zinc oxide nanoparticles (ZnO NPs) and microplastics (MPs) were extracted from one commercial sunscreen, while other ingredients were removed based on the "like dissolves like" principle. MPs were further extracted by acidic digestion of ZnO NPs using HCl and characterized as spherical particles of approximately 5 μm with layered sheets in an irregular shape on the surface. Although MPs were stable in the presence of simulated sunlight and water after 12 h of exposure, ZnO NPs promoted the photooxidation by producing hydroxyl radicals, with a 2.5-fold increase in the carbonyl index of the degree of surface oxidation. As a result of surface oxidation, spherical MPs were more soluble in water and fragmented to irregular shapes with sharp edges. We then compared the cytotoxicity of primary MPs and secondary MPs (25-200 mg/L) to the HaCaT cell line based on viability loss and subcellular damages. The cellular uptake of MPs transformed by ZnO NPs was enhanced by over 20%, and MPs caused higher cytotoxicity compared with the pristine ones, as evidenced by a 46% lower cell viability, 220% higher lysosomal accumulation, 69% higher cellular reactive oxygen species, 27% more mitochondrial loss, and 72% higher mitochondrial superoxide at 200 mg/L. Our study for the first time explored the activation of MPs by ZnO NPs derived from commercial products and revealed the high cytotoxicity caused by secondary MPs, providing new evidence on the effects of secondary MPs on human health.